curriculum training

Curriculum Training

Sensors and Actuators

Sensors

Technical Service TrainingCG 8233/S en 12/2006

TC4012041H

To the best of our knowledge, the illustrations, technical information, data and descriptions in this issue were correct at the time

of going to print. The right to change prices, specifications, equipment and maintenance instructions at any time without notice

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can be accepted for any inaccuracies in this publication, although every possible care has been taken to make it as complete and

accurate as possible.

Copyright ©2007

Ford-Werke GmbH

Service training programs D-F/GT1 (GB)

Electronics as well as measurement and control technology are playing an increasingly important role in automotive

engineering.

Sensors are used to register measurement variables for a variety of electronic control systems related, e.g. to the

engine, chassis, safety and comfort.

These sensors register, for example, values indicating angle, acceleration, speed, pressure, flow rate, temperature,

brightness, moisture, gas concentration and vibration, and transmit them as electrical signals to the inputs of the

relevant control modules.

The control modules use these signals to calculate variables for the control of actuators. Actuators do mechanical

work in order to open or close elements such as nozzles, valves or contacts.

The expression "sensor" is derived from the Latin word "sensus (= feel)". Sensor signals are formed using a variety

of electrical variables such as current, voltage, resistance, frequency, oscillation, amplitude, period, pulse duration,

capacitance, inductance.

Self-tests performed by control modules usually account for connected sensors and related wiring. System diagnosis

is performed using the WDS ( Worldwide Diagnostic System)/IDS (Integrated Diagnostic System).

The training course on sensors and actuators includes the following information for technicians:

– Sensors, CG 8233/S (TC4012041H)

– Actuators, CG 8234/S (TC4012042H)

– Communications Network, CG 8235/S (TC4012053)

For service purposes, this document provides an overview of the most commonly installed sensors and their functions

as well as diagnostic advice.

Note: The supplied data and values only serve as demonstration and to facilitate understanding. Current

values should always be taken from current workshop literature.

Please remember that our training literature has been prepared for FORD TRAINING PURPOSES only. Repairs

and adjustments MUST always be carried out according to the instructions and specifications in the workshop

literature. Please make full use of the training offered by Ford Technical Training Courses to gain extensive

knowledge of both theory and practice.

1Service Training (G458880)

Preface

Preface..............................................................................................................................

Lesson 1 – General Information

7Introduction................................................................................................................................................

7Open and closed loop control..........................................................................................................................................

8Testing sensors and switches...........................................................................................................................................

8Pulse width modulated signals........................................................................................................................................

10Group assignment.......................................................................................................................................

11Physical operating principles.....................................................................................................................

11Piezoelectricity................................................................................................................................................................

13NTC resistor....................................................................................................................................................................

14PTC resistor.....................................................................................................................................................................

15Inductance.......................................................................................................................................................................

17Membrane sensors with strain resistors..........................................................................................................................

18Hall effect........................................................................................................................................................................

21Magneto-resistivity.........................................................................................................................................................

22Capacitance.....................................................................................................................................................................

23Optoelectronics...............................................................................................................................................................

24Switches..........................................................................................................................................................................

26Reed contact....................................................................................................................................................................

27Ohmic resistance.............................................................................................................................................................

28Infra-red radiation...........................................................................................................................................................

29Ultrasonic........................................................................................................................................................................

31Photovoltaic effect...........................................................................................................................................................

32Galvanic principle...........................................................................................................................................................

Service Training2

Table of Contents

33Test questions..............................................................................................................................................

Lesson 2 – Sensors

35Sensors.........................................................................................................................................................

35Exhaust gas temperature sensor......................................................................................................................................

36Intake air temperature sensor (IAT)................................................................................................................................

38Barometric pressure sensor (BARO)...............................................................................................................................

40Outside air temperature sensor........................................................................................................................................

41Acceleration sensor (lateral/longitudinal acceleration sensor).......................................................................................

43Brake pad wear sensor....................................................................................................................................................

44Brake pressure sensor......................................................................................................................................................

46Brake-booster pressure sensor........................................................................................................................................

47Brake pedal travel sensor................................................................................................................................................

49Impact sensor (acceleration sensor)................................................................................................................................

51Torque-angle sensor........................................................................................................................................................

52Throttle position (TP) sensor (petrol engines)................................................................................................................

54Electronic differential pressure transducer / diesel particulate differential pressure sensor...........................................

56Vehicle speed sensor (VSS)............................................................................................................................................

58Accelerator pedal position (APP) sensor........................................................................................................................

62Transmission range (TR) sensor.....................................................................................................................................

64Remote transmitter..........................................................................................................................................................

66Transmission fluid temperature (TFT) sensor.................................................................................................................

68Gear-shaft speed sensors............................................................................................................................

68Output shaft speed sensor (OSS)....................................................................................................................................

68Input shaft speed sensor (ISS).........................................................................................................................................

68Turbine shaft speed sensor (TSS)....................................................................................................................................

3Service Training

Table of Contents

70Yaw rate sensor...............................................................................................................................................................

71Glass break sensor...........................................................................................................................................................

72Intrusion sensor...............................................................................................................................................................

74Refrigerant pressure sensor.............................................................................................................................................

75Knock sensor (KS)..........................................................................................................................................................

77Force sensor....................................................................................................................................................................

78Fuel pressure sensor........................................................................................................................................................

80Fuel level sensor..............................................................................................................................................................

82Fuel temperature sensor..................................................................................................................................................

84Clutch pedal position sensor (vehicles with hill launch assist).......................................................................................

85Crankshaft Position Sensor (CKP)..................................................................................................................................

88Engine coolant temperature sensor (ECT) and cylinder head temperature sensor (CHT)..............................................

91Oxygen sensors (HO2S).............................................................................................................................

91General............................................................................................................................................................................

92Dual-point HO2S (NTK)................................................................................................................................................

94Planar dual-point HO2S..................................................................................................................................................

96Planar broadband HO2S..................................................................................................................................................

98Steering wheel rotation sensor........................................................................................................................................

101Light sensor.....................................................................................................................................................................

103Mass air flow sensor (MAF)...........................................................................................................................................

107Air temperature sensor, air outlet temperature sensor....................................................................................................

109Inclination sensor............................................................................................................................................................

111Camshaft Position Sensor (CMP)...................................................................................................................................

113Oil level/temperature sensor...........................................................................................................................................

115Position sensor - gearshift actuator.................................................................................................................................

117Wheel speed sensor.........................................................................................................................................................

Service Training4

Table of Contents

120Rain sensor......................................................................................................................................................................

122Manifold absolute pressure sensor (MAP)......................................................................................................................

125Convertible top sensors (Focus Coupe Convertible).......................................................................................................

128Select-Shift switch..........................................................................................................................................................

130Passenger weight sensor..................................................................................................................................................

132Occupancy sensor...........................................................................................................................................................

134Seat position sensor.........................................................................................................................................................

136Sun load sensor...............................................................................................................................................................

138Position sensors (distance sensors).................................................................................................................................

139Intake manifold flap position sensor (diesel engines).....................................................................................................

142Ultrasonic sensor for parking aid....................................................................................................................................

144Test questions..............................................................................................................................................

Lesson 3 – Switches

146Pressure switch............................................................................................................................................

146Brake pressure switch.....................................................................................................................................................

147Refrigerant pressure switch.............................................................................................................................................

149Oil pressure switch..........................................................................................................................................................

150PSP (Power Steering Pressure) switch............................................................................................................................

151Mechanical switch......................................................................................................................................

151Brake light switch / brake pedal position (BPP) switch / clutch pedal position (CPP) switch.......................................

153Defrosting switch............................................................................................................................................................

154Seatbelt buckle switch.....................................................................................................................................................

156Rear door window switch strip.......................................................................................................................................

157Inertia fuel shutoff (IFS) switch......................................................................................................................................

158Brake fluid switch...........................................................................................................................................................

5Service Training

Table of Contents

159Switch for windshield washer / coolant level..................................................................................................................

160Reversing lamp switch....................................................................................................................................................

161Audio remote control......................................................................................................................................................

162Speed control switch.......................................................................................................................................................

163Other switches.................................................................................................................................................................

164Test questions..............................................................................................................................................

166Answers to the test questions.........................................................................................

167List of Abbreviations.......................................................................................................

Service Training6

Table of Contents

Open and closed loop control

To understand the importance of sensors, we first need

to examine the difference between open- and closed-loop

control. This difference can be demonstrated using two

examples provided below.

Open-loop control

E59373

1

25 3

4

EGR (Exhaust Gas Recirculation) solenoid valve1

PCM (Powertrain Control Module)2

Vacuum line3

EGR valve4

Recirculated exhaust gas quantity5

A characteristic is saved in the PCM. This characteristic

indicates how far the EGR valve must open in order to

achieve a particular recirculated exhaust gas quantity.

For every setpoint value (desired EGR rate), there is a

corresponding value of the manipulated variable

(setting of the EGRvalve).

Closed-loop control

E59374

1

5

63

4

2

EGR solenoid valve1

PCM2

Vacuum line3

EGR valve4


Position sensor in EGR valve6

The setpoint value (50% in this example) determined

for the EGR valve using the characteristic is compared

with the actual value from the position sensor

(measured variable, 45% in this example) on the

EGRvalve.

E59375

1

5

63

4

2

EGR solenoid valve1

PCM2

Vacuum line3

EGR valve4


IntroductionLesson 1 – General Information


Position sensor in EGR valve6

The difference between the setpoint value and actual

value (50% vis-à-vis 45% in this example) is used to

determine the actual setting of the EGR valve and

perform a correction (55% in this example) to the

manipulated variable.

Summary

The essential difference between open and closed-loop

control lies in the comparison of setpoint values with

corresponding measurement variables. Whereas

closed-loop control involves this comparison, open-loop

control does not.

Testing sensors and switches

Sensors installed in a vehicle have different

measurement principles depending on their task and

design.

To "measure" in this case means to "compare". In

other words, any value measured by the sensor needs

to correspond (within a defined tolerance range) to a

setpoint value defined for the state in question.

If measured values lie outside the tolerance range, the

sensor may be defective. In this case, it is also necessary

to check the connectors and cables for signs of damage

/ corrosion.

Pulse width modulated signals

PWM (Pulse Width Modulation) signals are

square-wave signals with a constant frequency, but

variable turn-on time.

E59696

Voltage (in volts)V

Timet

The frequency is determined by the number of pulses

(oscillations per second). Accordingly, the frequency

increases / decreases proportionally to the number of

pulses per second.

The frequency (formula symbol "f") is measured in

Hertz (Hz).

The pulse width is the duration of the active signal.

E59656

A

B

C

Voltage (in volts)V

50% active (500 ms on and 500 ms off)A

25% active (250 ms on and 750 ms off)B

75% active (750 ms on and 250 ms off)C

(G458890) Service Training8

Lesson 1 – General InformationIntroduction

The duty cycle is the ratio between the on and off times

of a PWM signal. The duty cycle is expressed as a

percentage (%).

Accordingly, a duty cycle of 25% means that the signal

is active 25% of the time; over 1 second of pulse width

modulation, for example, the signal is active for 250 ms

and inactive for 750 ms.

PWM signals can serve both as output signals (e.g.,

boost pressure solenoid valve) and as input signals (e.g.,

digital MAF (Mass Air Flow) sensor).

The duty cycle can be measured with the aid of an

oscilloscope and the WDS/IDS datalogger (if supported).


IntroductionLesson 1 – General Information

According to their function, sensors in vehicles can be

assigned to one of the groups below.

Piezoelectric, for example:

– Knock sensors

– Accelerometers

NTC (Negative Temperature Coefficient) resistor.

– Temperature sensors

PTC (Positive Temperature Coefficient) resistor.

– Temperature sensors

– Temperature control

Inductive, for example:

– Speed sensor

– Wheel-speed sensor

– Phase sensors

Membrane sensors with strain resistors:

– Pressure sensor

Hall effect, for example:

– Selector-lever position sensor

– Speed sensor

– Seat-position sensor

– Belt-buckle sensor

– Phase sensor

Magnetic-field sensors, for example:

– Steering-wheel rotation sensor

– Active wheel-speed sensor

Capacitive, for example:

– Yaw rate sensor

– Impact sensor

Switches, for example:

– Pressure cut-off switch

– Seatbelt buckle switch

– Reed contact - filling level indication

Ohmic resistance, for example:

– Potentiometer

– Voltage coding

– Seat occupancy detection

– Accelerator-pedal setting sensor

– Angle / position sensor

Infrared, for example:

– Rain sensor

– Infrared locking system (transmitter / receiver)

Ultrasonic, for example:

– Parking aid

– Interior monitoring

Galvanic, for example:

– Lambda sensor

Photovoltaic, for example:

– Solar sensor (photo-diode / transistor)

– Light sensor


Lesson 1 – General InformationGroup assignment

Piezoelectricity

The piezo-electric effect

E53584

2

5

A B C1

1 4

4

6

3

Quartz crystal in rest stateA

Action of an external forceB

Application of an electrical voltageC

Pressure1

Ion displacement2

Voltage generation3

Direction of force4

Deformation of crystal5

Voltage supply6

Piezo-technology finds application in optics, precision

mechanics, medicine, biology, consumer goods (e.g.

loudspeaker tweeters, quartz alarm clock beepers, etc.),

in mechanical engineering and the automotive industry.

Examples from the automotive industry include knock

sensors, pressure sensors, ultrasonic sensors,

acceleration sensors and actuators for opening fuel

injectors (on certain diesel engines).

The piezo-electric effect of natural crystals was

discovered in 1880 by the brothers Pierre and Jacques

Curie. The term piezo is derived from the Greek word

piezein, meaning to "press".

The piezo-electric effect can best be illustrated by means

of a quartz crystal, on which pressure is exerted.

Outwardly, the quartz crystal is electrically neutral in

its rest state, i.e. the positively and negatively charged

atoms (ions) are in balance (A).

External pressure exerted on a quartz crystal causes the

crystal's lattice to deform. This results in ion

displacement. An electric voltage (B) is generated as a

consequence.

Conversely, when an electrical voltage is applied, this

leads to a deformation of the crystal and consequently

to a force (C).



Uses of piezo-electricity in practice

E53585

5

A

B

7

4 6

1 2 3

Direct piezo effect (sensors)A

Indirect piezo effect (actuators)B

Solid body in rest state1

Force acting upon solid body (pressure)2

Force acting upon solid body (tension)3

Mechanical deformation of the solid body4

Elastic tension5

Force exerted6

Example application: Fuel injector7

Today's technologies use high-performance

piezo-ceramic materials instead of quartz crystals. When

it comes to applications, a distinction is made between

direct and indirect piezo effects.

The direct piezo effect is primarily utilized in sensors.

As sensors, piezo-ceramics convert a force acting upon

them into an electrical signal when the ceramic material

is compressed against its high rigidity.

Owing to dielectric displacement (dielectric =

electrically non-conductive), surface charges are

generated and an electric field builds up.

This field can be registered as a (measurable) electrical

voltage via electrodes.

Summary: In the case of sensors, mechanical energy

is converted into electrical energy by means of a force

acting on a piezo-electric body.

Example application:

– Knock sensor

The indirect piezo effect is primarily used in actuators.

In the case of actuators, electrical voltage is converted

into mechanical deformation of a solid body, i.e. an

electrical field acts upon a piezo-electric body,

deforming it.

If the body is prevented from deforming, elastic tension

is generated. Consequently, a force is exerted on the

structure preventing deformation of the piezo-electric

body.

Summary: In the case of actuators, voltage is applied

to the piezo-electric body, converting electrical into

mechanical energy.


– Fuel injector for the Siemens common rail system.



NTC resistor

Example characteristic of a NTC temperature sensor

E58741

R

T

ResistanceR

TemperatureT

In automotive technology, many temperature sensors

are equipped with a NTC resistor.

The core of a NTC temperature sensor is a

temperature-dependent, non-linear measuring resistor

in the form of a semiconductor.

The resistance of the NTC component decreases as the

temperature increases.

Accordingly:

– The higher the temperature, the lower the

resistance.

NTC-resistors are also termed thermistor.

NTC temperature sensors form part of a voltage-divider

circuit usually supplied with a reference voltage of 5 V.

The voltage drop across the NTC resistor depends on

the prevailing temperature. This voltage value is used

by the connected control unit as a measure of the sensor

temperature.

The base material consists of different oxides of metals

such as iron, cobalt, nickel, copper and zinc. Chemical

stabilizers are added to the oxides, which are then

pressed into the desired shape.


– ECT (Engine Coolant Temperature) sensor

– IAT (Intake Air Temperature) sensor

General testing possibilities

For the purpose of testing, the NTC temperature sensor

can be represented in the DMM (in some cases, also in

the WDS/IDS datalogger) and its reading compared

with the actual sensor temperature measured using a

standard thermometer.

More detailed sensor tests can be performed by heating

the sensor with a hot air blower or cooling it with a

temperature reduction spray.

The values measured here must correspond to the

setpoint values. Furthermore, the resistance

characteristic must remain constant.



PTC resistor

Example characteristic of a PTC resistor

E59807

R

T

ResistanceR

TemperatureT

The PTC resistor is an electrical component whose

resistance increases with temperature.

Accordingly:

– The higher the temperature, the higher the

resistance.

PTC resistors are also referred to as posistors.

PTC resistors are used mainly to limit temperatures.

The power consumption of the PTC is controlled

automatically by its characteristic.

A higher current flows at the low temperatures

prevailing immediately after a PTC resistor has been

connected (due to the lower resistance in this phase).

As the temperature increases, so does the resistance,

causing the current to drop correspondingly.

Advantage:

– This characteristic prevents the PTC element from

overheating.


– Auxiliary electric heater on diesel vehicles

General testing possibilities

For the purpose of testing, the PTC temperature sensor

can be represented in the Datalogger or DMM and its

reading compared with the actual sensor temperature

measured by means of a standard thermometer.

More detailed sensor tests can be performed by heating

with a hot air blower or cooling with spray.

The values measured here must correspond to the

setpoint values. Furthermore, the resistance

characteristic must remain constant.



Inductance

Generating an induction voltage

E58742

1

4

2

3

Motion1

Electrical conductor2

Permanent magnet3

Magnetic field4

The diagram shows a permanent magnet with north and

south poles. An electrical conductor is positioned

between the north and south poles.

If the conductor is moved in the direction of the arrow,

it intersects with the permanent magnet's field lines.

Charges inside the conductor are displaced in this

process. Free electrons move to one end of the

conductor. Correspondingly, a shortage of electrons

occurs at the other end.

The resulting potential between the conductor's ends is

termed induction voltage.

The induction voltage's direction depends on the

electrical conductor's direction of motion and the

magnetic field's direction.

E58743

2

1

Amplitude1

One complete oscillation = 1 period2

Voltage in voltsU

Time in secondst

Voltages generated by induction constantly alternate in

level and polarity. Accordingly, they are also termed

alternating voltage.

Alternating voltage rises from 0 V to its positive peak

value (amplitude), then drops back via the 0-V level to

its negative peak value, rises again to its positive peak

value etc. The number of complete alternations (periods)

per second is termed the voltage frequency.


– Inductive CKP (Crankshaft Position) sensor

– Passive wheel speed sensor



Practical example involving a passivewheel-speed sensor

E58802

1

6

2 3

45

Permanent magnet1

Coil2

Magnetic field3

Sensor ring (pulse generation wheel)4

Air gap5

Connection cable6

The inductive wheel-speed sensor contains a permanent

magnet surrounded by a coil.

The wheel-speed sensor is mounted so that its front face

is a defined distance from the sensor ring.

The rotation of the pulse generation wheel influences

the magnetic field. The changes in the magnetic field

induce an alternating voltage in the inductive sensor

coil.

The signal frequency changes as the wheel speed

increases or reduces. The control unit (the ABS

(Anti-lock Brake System) module in this case) receiving

the frequency signal uses it as a measure of the current

wheel speed.

Self-induction

When a current starts flowing through an electrical

conductor, a circular magnetic field originating from

the center of the conductor is produced.

The strength of this magnetic field is proportional to the

current intensity. The magnetic field's polarity depends

on the current's direction of flow.

If an insulated conductor is wound on a coil form, the

magnetic fields of the individual windings are added

together to form a total force field.

Conditions for induction are also present during build-up

of the magnetic field, causing a voltage to be induced.

However, this voltage opposes the excitation voltage

which generated it.

As no external factors are responsible for this, one

speaks here of self-induction. The same phenomenon

occurs in reverse when the coil's excitation voltage is

turned off.



Membrane sensors with strain resistors

Micro-mechanical membrane sensors with strain

resistors are often used to measure pressure in

automotive engineering.

Signals are generated by a thin membrane acting as an

intermediate mechanical stage; subjected at one end to

pressure, this membrane bends as a result.

Depending on the pressure values to be registered by

the sensor, the membrane can be adapted in terms of

thickness, diameter and material.

E58744

5

4

2

3

1

Strain resistor (compressed state)R1

Strain resistor (tensioned state)R2

Supply voltageU0

Measurement voltageUM

Measurement pressurep

Membrane1

Reference vacuum2

Glass (pyrex)3

Bridge circuit4

Silicon chip5

The sensor membrane bends in accordance with the

pressure applied to it.

The resulting mechanical forces change the electrical

resistances of the four expanding elements on the

membrane.

These four expanding elements are arranged on the

membrane such that the measuring resistance of two

increases, and that of the other two decreases.

The strain resistors are connected in a Wheatstone bridge

circuit. Changes in resistance also change the ratios

between the voltages across the measuring resistors.

The measurement voltage "UM" also changes

accordingly, thus serving to indicate the pressure exerted

on the membrane.

Example applications:

– MAP (Manifold Absolute Pressure) sensor

– BARO (Barometric Pressure) sensor

– Fuel pressure sensor



Hall effect

The physicist Edwin Hall made the following

discovery:

– If a current flows through an electrical conductor

positioned at right angles (90°) to a magnetic field,

the charge carriers (electrons) are deflected (Lorentz

force).

E59007

1 2

3

Hall plate1

Electron flow2

Magnetic field3

Supply voltageU

Hall voltageUH

The Hall effect here is generated by means of a

semiconductor plate (Hall plate) which receives a

defined voltage (U).

Application of the supply voltage "U" results in an

evenly distributed electron flow over the entire surface

of the Hall plate. As a result, a magnetic field builds up

around the Hall plate.

The evenly distributed electron flow leads to charge

equalization ("UH" = 0 V) on both sides of the Hall

plate.

Example, part 1:

E59008

12

3

4

Hall plate1

Electron flow2

Magnetic field3

Permanent magnet4

Supply voltageU

Hall voltageUH

Switching point 1S1



Note: Changes in the magnetic field lead to

corresponding changes in electron flow.

If the north pole of a permanent magnet meets the north

pole of a Hall plate's magnetic field, the field moves

away from the permanent magnet.

As a result, the electrons (negatively charged particles)

driven by the longitudinal potential are suddenly

deflected vertically with respect to the current's direction

of flow, away from the permanent magnet (repulsion

of electron flow).

The resulting charge difference between the two sides

of the Hall plate gives rise to a Hall voltage ("UH").

Example, part 2:

E59020

12

3

4

Hall plate1

Electron flow2

Magnetic field3

Permanent magnet4

Supply voltageU

Hall voltageUH

Switching points 1 to 3S1 to

S3

If the south pole of a permanent magnet meets the north

pole of a Hall plate magnetic field, the field moves

toward the permanent magnet.

As a result, the electrons (negatively charged particles)

driven by the longitudinal potential are suddenly

deflected vertically with respect to the current's direction

of flow, toward the permanent magnet (attraction of

electron flow).

The sudden changes in electron flow correspondingly

change the polarity of the Hall voltage (from positive

to negative or vice versa).

The Hall voltage is generally very low. Lying in the

millivolt range, these voltages must be processed

appropriately.

Sensor technology usually makes use of integrated

circuits (ICs) to process Hall voltages and output them

as square-wave signals to the terminal device (e.g.

PCM). The square-wave signals can be made visible

with the aid of an oscilloscope.

Note: The Hall plate magnetic field can also be deflected

by moving an iron element (e.g., a ferrous pulse wheel)

toward it.

Example involving a ferrous pulse wheel

In this case, there is no alternation of electron flow

between the sides of the Hall plate.

The magnetic field and electron flow are always

displaced in just one direction: from charge

equalization to charge difference (0 signal edge / high

signal edge).




– CMP (Camshaft Position) sensor (based on Hall

effect)

– VSS (Vehicle Speed Sensor) (based on Hall effect)



Magneto-resistivity

Alignment of local magnetization in a ferromagnetic

material with and without the influence of an external

magnetic field

E53537

1 2

Without external magnetic influence1

With external magnetic influence2

The magnetoresestive effect is based on the alignment

of local magnetizations in ferromagnetic materials.

Ferromagnetic materials consist of several layers. Each

one of these layers has a local magnetization.

Without the influence of an external magnetic field, the

alignment of the local magnetization is random.

If an external magnetic field is applied to the

ferromagnetic material, the local magentizations are

aligned towards the external magnetic field.

The alignment of the local magnetization is dependent

on the strength of the external magnetic field:

– If the magnetic field is weak, the alignment of the

local magnetization to the external magnetic field is

random and therefore uneven. The ferromagnetic

material has a high resistance.

– If the magnetic field is sufficiently strong, the

alignment of the local magnetization to the external

magnetic field is uniform. The ferromagnetic

material has a low resistance.

The ferrous material used is, for example, an alloy of

80% nickel and 20% iron (permalloy).


– Steering-wheel rotation sensors

– Wheel speed sensors



Capacitance

Capacitive measurement is based on the principle of a

capacitor.

One of the physical properties of a capacitor is the

dependence of its capacitance, i.e. ability to store charge,

on the distance between its two plates. The plate spacing

accordingly determines the charge difference between

the two plates.

Capacitive measurements make use of this property.

E53938

If the two plates are relatively far apart, the charge

difference between them is relatively low.

E53939

If the plates are moved closer together, the charge

difference rises proportionally.

The change in charge difference can be registered and

evaluated by a connected control unit.


– Brake pressure sensor in an ABS system

– Acceleration sensor



Optoelectronics

E53330

2

1

3

Segment disk1

Light beam2

Photoelectric barrier, consisting of transmitter

and receiver

3

Optoelectronic sensors use photoelectric barriers for

contactless monitoring of a sender element.

The sender element could be e.g. a segment disk (see

illustration). The gaps on the edge of the segment disk

allow the light beams to pass, the solid material between

them break the light beam of the photoelectric barrier.

The number of times the light beam is broken indicates

the distance traveled.


– Steering-wheel rotation sensors



Switches

On / off switches and changeover switches, or buttons

are not sensors in the conventional sense.

Nevertheless, these components are worthy of mention

when speaking of sensor technology, because they can

transfer pressure signals as well as mechanical switch

settings, limits and angular values for further processing

to the control electronics by establishing a connection

to earth or a positive pole. These components are also

used for thermal protection.

Switches are used, for example, to input instructions for

the speed control system, in which case different

resistance values are connected to the signal input of

the electronic control unit.

Voltage coding

In the case of voltage coding, an electronic control unit

registers voltage drops via an array of integrated

resistors and determines which resistor (control

instruction) was connected into the circuit in each case.

One advantage of this type of circuit is the relatively

low number of connected cables.

Speed-control system using the Scorpio '95 as an example

TIE41680

-

A

ON button actuated.

Voltage supplyA

To the speed control module / PCM5. 6

The switches are linked via a hybrid circuit with the

control unit / PCM speed control unit.

Different resistors are integrated into the circuit.

Pressing a button supplies the control unit with a voltage

signal whose value depends on the connected resistance.

The control unit uses this signal to identify the button

which was pressed, and then adjusts the vehicle's speed

taking into account all necessary parameters.



TIE41681

-

Acceleration / SET button operated

Voltage supplyA

To the speed control module / PCM5. 6

Pressing the acceleration button (corresponding here to

approx. 680 ohms between pins 5 and 6) produces a

voltage drop in the electric circuit. This drop is identified

by the control module as an acceleration signal.

Pressing any of the other buttons also connects an

associated resistor which results in a corresponding

voltage drop. In accordance with the registered drop,

the module invokes a related function from memory.


– Electric seat adjustment

– Electronic mirror adjustment

– Radio remote control

– Select-shift switch on the steering wheel (in vehicles

with automatic transmission and manual gear

selection)

– Cruise control system



Reed contact

E59704

2

2

1

Closed reed contact

Glass tube1

Contact tips2

A reed contact reacts to changes in low current or

movements of permanent magnets without making any

physical contact.

Depending on the type of circuit, two or three contact

tips are fused into a glass tube containing a vacuum or

inert gas.

E59705

23

2

1

Open reed contact

Glass tube1

Contact tips2

Permanent magnet3

One of the contact tips is magnetized and reacts very

sensitively to the lines of force generated by a permanent

magnet or electrical field.

Because they are protected, the contacts have a nearly

unlimited service life.

Reed contacts can be normally open or closed.


– Tank flap switch for vehicles with a soot particle

filter and fuel additive system

– Liquid level switch



Ohmic resistance

In sensor technology, ohmic resistances are employed

in accordance with the voltage division principle.

Fixed ohmic resistances

Fixed ohmic resistances of different values serve, for

example, to indicate control commands, lever settings,

angular positions etc. in the sensor loop of a control

unit's input section.

In the case of a speed-control system, for example,

resistors of different values are connected to the signal

input loop of the electronic control module (refer to the

description of switches).

Sliding-contact position sensor

E59775

4

5

B

A

1

3

2

Maximum angle of rotationA

Current measuring angleB

Variable resistance track1

Maximum resistance2

Contact track3

Sliding contact4

Minimum resistance5

In the case of a sliding-contact sensor (or potentiometer),

a contact slides at a defined angle over a variable

resistance track.

The variable resistance track is designed to have a

constant, rising or falling resistance characteristic from

start to end.

The sensor is supplied with a reference voltage via the

contact track. This contact track has a constant, low

ohmic resistance from start to end.

When the sliding-contact position sensor is actuated,

the resistance of the variable resistance track changes

correspondingly. At the same time, the voltage drop

across the variable resistance changes proportionally,

thus serving to indicate the current position.


– APP (Accelerator Pedal Position) sensor

– TP (Throttle Position) sensor



Infra-red radiation

Infrared radiation lies in the optical waveband and forms

part of the electromagnetic spectrum. The infrared range

is adjoined by visible light of long wavelengths.

Every "warm" body (i.e. with a temperature in excess

of absolute zero, or -273°C) emits infrared radiation.

The radiated energy and wavelength distribution depend

on the body's temperature. The higher a body's

temperature, the more energy it releases in the form of

infrared radiation.

Infrared radiation is often used for contactless transfer

of heat signals.


– Infra-red remote control

– Rain sensor



Ultrasonic

An ultrasonic sensor operates at brief time intervals

alternately as a transmitter and receiver.

During these measurement cycles, the ultrasonic sensor

transmits ultrasonic waves of a certain frequency (in

excess of 16 kHz) inaudible to humans.

An ultrasonic sensor consists of a piezo-element with

a conical member. Acting as a reverse funnel, the cone

pushes waves outward through an opening in the

housing.

E59570

2

3

4

1

Cone1

Housing2

Piezo element3

Electrical connection4

The piezo element consists of two differently sized piezo

plates.

Piezo element

E59571

4

3

2

1

Ultrasonic waveA

Long plate1

Ultrasonic wave generated by voltage2

Voltage generated by ultrasonic wave3

Short plate4

On receiving a voltage via an electrical connection,

these plates expand. In this process, the shorter plate

exerts pressure on the longer one, similar to a bi-metallic

strip.

The resulting stress between the two plates causes them

to oscillate at a high frequency.

The sensor transmits these oscillations as ultrasonic

waves.

The speed of sound in air is 343 metres per second (m/s).

On meeting an obstruction, sound waves are reflected.

The sensor receives the resulting echo signal after a time

proportional to the distance travelled by the sound.

The total time is that taken by sound signals to travel

from the ultrasonic sensor to the obstruction and back.



The electronic evaluation module then calculates the

distance to the obstruction using the speed of sound.

The total time elapsed between transmission of the

sound signal and reception of the echo signal is divided

by two.

Example:

– If the distance between the ultrasonic sensor and

reflective obstruction is 0.5 metres, the sound signal

covers 1 metre in travelling to and fro.

– Formula: > 1 s : 343 m = 0.0029 s or 2.9 ms

– A travelling time of 2.9 ms corresponds to a distance

of 0.5 m. At a distance of one metre, the signal

travelling time would be 5.8 ms.


– Parking aid sensors

– Intrusion sensors

Radiation of ultrasonic waves by a parking aid sensor

E59085



Photovoltaic effect

Photovoltaic technology involves a conversion of solar

energy into electrical energy (voltage).

A solar cell is a photodiode made of semiconductor

material (e.g., germanium, silicon, selenium).

If visible (laser) or invisible (infrared) light radiation

impinges on the semiconductor's crystalline structure,

electrons are dissociated from their atoms. This gives

rise to an open-circuit voltage between the anode and

cathode.

The conductivity of the resulting electrical path increases

with the radiation intensity.

Because photodiodes are operated in the reverse

direction, one speaks of a reverse current in this case.

The reverse current is proportional to the intensity of

the impinging light.

Photodiodes and photo-transistors are used as sensors

for light-dependent control.


– Solar sensor

– Light sensor

Photovoltaic cell

A photovoltaic cell is a solar cell (photodiode) suitable

for use as a power source.

Photo-transistor

As opposed to a conventional transistor, a

photo-transistor has a light-sensitive semiconductor

layer instead of a base.

In sensor technology, photo-transistors are used as

light-sensitive switches. When light impinges on a

photo-transistor, the path between its collector and

emitter becomes conductive.

Light-dependent resistor (LDR)

Also comprising a light-sensitive semiconductor

element, a light-dependent resistor varies its resistance

in accordance with the intensity of the light impinging

on it.

Made of cadmium sulphate, a light-dependent resistor

contains very few or no free electrons in darkness.

The resistance in darkness is very high (several hundred

kohms). When light impinges on the LDR, electrons

are released and the LDR becomes conductive.

Resistance in bright conditions is lowered to a few

hundred ohms.

In principle: The higher the light intensity, the lower

the resistance.

LDR designs

E59849



Galvanic principle

E58871

1 3

2

Metal 11

Electrolyte solution2

Metal 23

A galvanic element consists of two different metals in

an electrolyte solution.

The metals in the solution give rise to different levels

of ionization resulting in a corresponding displacement

of electrons.

This generates a voltage potential between the two

metals.


– Vehicle battery

– HO2S (Heated Oxygen Sensor)

Conventional oxygen sensors basically operate like

galvanic elements, except that they are equipped with

a solid electrolyte - zircon dioxide (ZrO2) - instead of

a liquid electrolyte.

At temperatures in excess of 300°C, this ceramic

electrolyte permits a passage of oxygen ions while

blocking electrons.



Tick the correct answer or fill in the gaps.

1. A comparison between setpoint values and actual measurement values takes place:

a. exclusively during transmission control.

b. exclusively during engine control.

c. during open-loop control.

d. during closed-loop control.

2. What are PWM signals?

a. Square-wave signals of a variable frequency

b. Square-wave signals of a constant frequency

c. Sinusoidal signals of a constant frequency

d. Temperature-dependent direct voltages

3. All speed sensors are inductive:

a. True

b. False

4. Which principle do temperature sensors operate on?

a. Hall

b. Inductive

c. Ohmic resistance

d. NTC.

5. In the case of NTC resistors:

a. the higher the temperature, the higher the resistance.

b. the higher the temperature, the lower the resistance.

c. the higher the temperature, the higher the duty cycle.

d. the higher the temperature, the higher the signal frequency.


Test questionsLesson 1 – General Information

6. In the case of voltage coding:

a. use is made of different resistance values.

b. a large number of signal lines is needed.

c. codes indicating voltage values are exchanged between control units.

d. use is made exclusively of resistances between 300 and 500 ohms.

7. Which of the following statements is false?

a. In piezo technology, a distinction is made between direct and indirect piezo effects.

b. The value of a PTC resistor increases with its temperature.

c. Hall signals can generally not be made visible with the aid of an oscilloscope.

d. During inductive speed measurement, the signal frequency changes correspondingly as the speed rises.


Lesson 1 – General InformationTest questions

Exhaust gas temperature sensor

E59692

Location

In the exhaust system upstream of and/or downstream

of the catalytic converter

Physical operating principle

PTC resistor (1.8L Duratec-SCi)

NTC resistor (1.6L/2.0L Duratorq-TDCi with diesel

particulate filter)

Task / function

The exhaust gas temperature sensor measures the

temperatures of the exhaust gases.

The resistance, and so the voltage drop at the sensor,

alter depending on the exhaust temperature.

Operating range

Value

Approx. 5 VReference voltage

Direct voltage: 0.2-4.8 VSignal type / voltage

see tableResistance

–Frequency

Values of the exhaust gas temperature sensor in the

1.8L Duratec-SCi

Resistance (ohm)Temperature (°C)

210 – 23020

480 – 500400

Measuring options

CompatibilityDiagnostic tool

YesWDS/IDS DTC

(Diagnostic Trouble Code)

++Guided diagnostics (WDS/

IDS)

+DMM

++Datalogger

–Oscilloscope (breakout

box and adapter cable

required)

– –Powerprobe

++ very suitable, + suitable

- unsuitable, - - very unsuitable


SensorsLesson 2 – Sensors

Intake air temperature sensor (IAT)

E58186

1 2

Examples of IAT sensors

IAT sensor 2.4L Duratorq-DI (Puma) diesel1

IAT sensor 2.0L Duratorq-TDCi (Puma) diesel2

Location

In the intake system


NTC resistor

Task / function

The IAT sensor measures the current intake air

temperature.


alter depending on the intake air temperature.

Operating range

Value



see tableResistance

–Frequency

IAT sensor set values in Visteon systems *

Voltage (V)Resistance

(Kohms)

Temperature

(°C)

4.51 – 4.54860 – 900– 40

4.46 – 4.49501 – 645– 30

4.31 – 4.35253 – 289– 20

4.17 – 4.23170 – 196– 10

3.82 – 3.9289 – 1020

3.5 – 3.762.0 – 70.010

3.0 – 3.235.0 – 40.020

2.6 – 2.825.0 – 28.030

2.0 – 2.215.0 – 17.040

1.7 – 1.911.0 – 13.050

1.2 – 1.47.1 – 8.060

0.9 – 1.25.0 – 6.270

0.6 – 0.93.0 – 4.580

0.5 – 0.72.4 – 3.590

0.4 – 0.51.9 – 2.5100

0.3 – 0.41.5 – 1.7110

0.2 – 0.31.0 – 1.3120

* IAT values of other engine-management systems may differ from

this table.

Measuring options


YesWDS/IDS DTC


IDS)

++DMM




+Datalogger



required)

– –Powerprobe



Special features

The IAT sensor is often integrated into the following

components:

– in the MAF sensor (it is then designated as the

"combined IAT sensor" and "MAF sensor")

– in the MAP sensor (it is then designated as the

MAPT (Manifold Absolute Pressure And

Temperature) sensor)

However, the properties of the integrated IAT sensor

are identical to those of the separate IAT sensor.

On some systems, the IAT sensor signal is also used for

calculating the battery electrolyte temperature.



Barometric pressure sensor (BARO)

E58180

1

2

BARO sensor1

PCM2

Location

Integrated in the PCM.

Exception: 2001 Mondeo with 2.0L Duratorq-TDCi

(Puma) with the VP44-injection pump and variable

turbocharger:

– in the inner area behind the instrument panel, at the

left support of the reinforcement element of the

A-pillar.



Task / function

The BARO sensor measures the ambient pressure.


alter depending on the ambient pressure.

Operating range

Value



adjustable *Resistance

adjustable *Frequency

* In some systems, the BARO in the datalogger is displayed in

millibars (mbar), and in others in hertz (Hz).

Measuring options


YesWDS/IDS DTC


IDS)

+ (not possible with the

sensor integrated in the

PCM)

DMM

++Datalogger

+ (not possible with the

sensor integrated in the

PCM)

Oscilloscope (breakout


required)

– –Powerprobe



Special features

Regardless of the operating state of the engine/vehicle,

the pressure must always remain constant and may only

change proportionally if there is a corresponding change

in the vehicle height (higher position, lower air

pressure).



In some systems, a BARO value is displayed in the

datalogger although no BARO sensor is installed. This

is merely a value calculated by the PCM.



Outside air temperature sensor

TIE42059

Location

In the front-end area, behind the bumper.


NTC resistor

Task / function

The outside-temperature sensor measures the ambient

temperature outside the vehicle.


alter depending on the outside-air temperature.

Operating range

Value



see tableResistance

–Frequency

Resistance (Kohms)Temperature (°C)

Approx. 5.20

Approx. 4.55

Approx. 3.910

Approx. 3.315

Approx. 2.820

Approx. 2.425

Approx. 2.030

Approx. 1.240

Measuring options


YesWDS/IDS DTC


IDS)

+DMM

+Datalogger



required)

– –Powerprobe





Acceleration sensor (lateral/longitudinalacceleration sensor)

E58049

1

2

Separate yaw rate/lateral acceleration sensor

(joint holder)

1

Combined yaw rate and lateral acceleration

sensor

2

Location

On the floor panel in the vehicle interior, at the

longitudinal and/or transverse axis


Capacitive

Task / function

Acceleration sensors measure the acceleration of the

vehicle in either a longitudinal or lateral direction,

depending on the use.

The higher the acceleration registered by the sensor, the

greater the sensor signal.

Operating range

Value

Approx. 12 VSupply voltage

Digital CAN protocol 5

V

Signal type / voltage

–Resistance

500 KB/sec.Frequency

Measuring options


YesWDS/IDS DTC


IDS)

– –DMM

++Datalogger

- (can not be evaluated)Oscilloscope (breakout


required)

– –Powerprobe



Acceleration sensors are monitored continuously by the

ABS/stability assist module.

When checking the acceleration sensor using the

datalogger, please note that even the smallest jolts will

be detected and displayed.

However, only a general function test is possible.

Evaluation of the signal is not possible using WDS/IDS.



Signal trace of the acceleration sensor in the datalogger

E59083

1

2

Minor jolt of the vehicle1

Major jolt of the vehicle2

Special features

In the case of relatively old vehicles, the acceleration

sensor may be installed as a separate component.

In some systems, it may be necessary to calibrate the

acceleration sensor using WDS/IDS after renewal.

Instructions for this can be found in the relevant Service

literature.



Brake pad wear sensor

TIE41547

Location

On the brake pad (for disc brakes only)


Ohmic resistance

Task / function

The brake pad wear sensor consists of a small wire loop

which is incorporated in the inner pad of a pair of brake

pads.

As soon as the friction lining of the brake pad has worn

down to a defined thickness, this leads, depending on

the system:

– A: to a break in the circuit to ground

– B: to a ground short

Operating range

Value


ON/OFFSignal type /

voltage

< 0.5 Ohm, wire coil not inter-

rupted

> 10 kOhm, wire coil interrupted

Resistance

–Frequency

Measuring options


NoWDS/IDS DTC

– –Guided diagnostics (WDS/

IDS)

++DMM

– –Datalogger

– –Oscilloscope (breakout


required)

– –Powerprobe



Special features

In the case of relatively old vehicles, resistors may also

be integrated into the circuit, which indicate a break in

the power supply with various displays in the instrument

cluster (indicator light flashes or shines continuously).



Brake pressure sensor

E58050

1

2

Brake pressure sensor integrated into the HCU

(Hydraulic Control Unit)

1

Brake-pressure sensor installed in the brake

master cylinder

2

Location

Depending on the type of ABS/stability assist installed,

the pressure sensors are either installed on the exterior

of the brake master cylinder or integrated into the HCU.


Capacitive, piezo or membrane sensors with strain

resistors

Task / function

The brake-pressure sensor measures the pressure in the

hydraulic brake circuit.

The sensor produces a voltage signal proportional to

the pressure.

Operating range

Value



–Resistance

–Frequency

Measuring options


YesWDS/IDS DTC


IDS)

+ (not with integrated

sensor)

DMM

++Datalogger

- (not with integrated

sensor)



required)

– –Powerprobe



Pressure sensors are monitored continuously by the

ABS/stability assist module.



Signal trace of the brake-pressure sensor in the datalogger

when the brake pedal is actuated twice

E59081

Capacitive pressure sensor

E53937

1

2

35

4

Brake master cylinder1

Brake fluid2

Sensor body3

Capacitive plate (movable)4

Capacitive plate (fixed)5

As hydraulic pressure rises, the movable plate of the

capacitive pressure sensor is pushed against the spring

by the piston.

The resulting charge transfer is picked up and evaluated

by the ABS/stability assist module.

Piezo-electric pressure sensor

E53980

2 3

1

Sensor body1

Piezoelectric actuator2

Electrical connector3

The piezo-electric pressure sensor consists of a piezo

element which is connected to the hydraulics of the

brake system via a membrane.

As brake pressure rises, the membrane deforms the piezo

element thereby changing the charge distribution in the

piezo element.

This change in charge distribution is evaluated by the

ABS/stability assist module to determine its magnitude.

Special features

The brake pressure sensors integrated into the HCU can

not be renewed separately.

In some systems, it may be necessary to calibrate the

brake pressure sensor with WDS after renewal.

Instructions for this can be found in the relevant Service

literature.



Brake-booster pressure sensor

TIE42041

Location

On the brake booster (Mondeo with 1.8L Duratec-SCi

(MI4))



Task / function

The brake-booster pressure sensor measures the vacuum

in the brake booster.


alter depending on the brake-booster pressure.

Operating range

Value



–Resistance

–Frequency

Measuring options


YesWDS/IDS DTC


IDS)

+DMM

+Datalogger



required)

– –Powerprobe



Voltage (V)Conditions

3.5 – 4.5 VWith the ignition ON,

operate the brake pedal

several times (decrease

vacuum in the brake

booster)

0.4 – 1.0 VWith the engine running

after several sharp blips of

the throttle (maximum

vacuum in brake booster)



Brake pedal travel sensor

E53982

Location

In the brake master cylinder (ABS with open return

only).


Sliding-contact switch

Task / function

The brake-pedal sensor measures the position of the

brake pedal.

The brake pedal sensor features two slide paths. One of

the two slide paths is divided into seven segments,

whereby each segment is connected via a resistor to one

of the electrical connections of the sensor.

E53983

2

3

1

4

Slide path1

Slider2

Resistor3


The other slide path is continuous and connected to the

second connection of the sensor. Depending on the

position of the pedal, the resistances are switched in

series via a sliding contact.

This results in a two-stage (Escort/Orion) or seven-stage

(Scorpio/Transit) resistance and/or voltage change across

the entire pedal travel.

Operating range

Value



see tableResistance

–Frequency



Resistance (ohm)Brake pedal position

237 – 262Stage 1 Escort/Orion 1991

(8/1990-9/2001)

974 – 1075Stage 2

237 – 249Stage 1 (Scorpio 1995 (10/

1994-6/1998) / Transit

1995 (8/1994-7/2000))

414 – 458Stage 2

535 – 591Stage 3

655 – 725Stage 4

776 – 858Stage 5

981 – 1083Stage 6

infiniteStage 7

Measuring options


YesWDS/IDS DTC

–Guided diagnostics (WDS/

IDS)

++DMM

– –Datalogger



required)

– –Powerprobe





Impact sensor (acceleration sensor)

E58051

1 2

3

Examples of impact sensors

Front and side impact sensor, Fiesta 2002.251

Front and side impact sensor, Mondeo 20012

Side impact sensor, Mondeo 19973

Location

Between one and five impact sensors are installed,

depending on the vehicle. Depending on use, they are

integrated at the vehicle front end (front air bag), on the

vehicle floor in the B-pillar area (for side air bag),

C-pillar (side air curtain in the case of more than two

seat rows) or in the SRS (Supplemental Restraint

System) module.


Piezo or capacitive

Task / function

Depending on the use, the impact sensors measure the

transverse and/or longitudinal acceleration of the

vehicle.

An electronic evaluation module is integrated in the

sensor. Digitally coded crash data is transmitted to the

SRS module according to the acceleration.

Operating range

Value

–Voltage

Digitally coded crash

data *


–Resistance

–Frequency

* Not measurable

Measuring options


Yes *WDS/IDS DTC


IDS)

– –DMM

– –Datalogger



required)

– –Powerprobe



* Depending on the system, the WDS/IDS indicates diagnostic

trouble codes together with the corresponding error values. Error

values are needed for error description in the FordEtis diagnostic

and test routine.

Impact sensors can not be checked in the workshop. It

is only possible to check the wiring.



Special features

Impact sensors are also designated as ECS (Electronic

Crash Sensor)s.

Due to their position, sensors for side air bags are also

referred to as satellite sensors.

In some systems, it is necessary to progam or calibrate

impact sensors in the SRS module after renewal.

In some systems, impact sensors can be reused after an

accident during which the air bags have been deployed.

The instructions in the current service literature must

be followed without fail.



Torque-angle sensor

E58067

Location

In the distributor injection pump VP30/VP44.


Hall

Task / function

The torque-angle sensor probes a pulse generation wheel

with fine splines. Precisely calculated gaps are worked

into the splines.

Operating range

Value

–Voltage

–Signal type / voltage

–Resistance

–Frequency

Measuring options


YesWDS/IDS DTC


IDS)

– –DMM

– –Datalogger



required)

– –Powerprobe



The torque-angle sensor itself can not be tested because

it is connected directly to the pump control unit (PCU).

The torque-angle sensor can not be replaced separately.

In the case of a defective torque-angle sensor, the entire

distributor injection pump must be replaced.



Throttle position (TP) sensor (petrolengines)

E31517

Location

In the intake tract in the throttle body


Sliding-contact potentiometer

Task / function

If the throttle plate is opened, a sliding contact moves

onto a resistance track in the TP sensor.

The resistance of the sensor increases proportionally as

the throttle plate is moved towards WOT (Wide Open

Throttle).

Operating range

Value


Direct voltage: 0.6-4.8

Volt


see tableResistance

–Frequency

Values of the TP sensor in the 2.0L Duratec-HE


(Kohms)

Throttle Position

Approx. 0.8Approx 1.1 *fully closed

Approx. 4.7Approx 4.4 *fully open

* Values measured on a removed TP sensor.

Measuring options


YesWDS/IDS DTC

+Guided diagnostics (WDS/

IDS)

+DMM

++Datalogger

++Oscilloscope (breakout


required)

– –Powerprobe



Signal trace of the TP sensor in the datalogger when

revving the throttle up twice.

E58350



Continuity test

With the aid of the oscilloscope, a continuity test can

be carried out on the signal wire of the TP sensor.

For this purpose, move the throttle plate continuously

from idling to WOT. The voltage change must also be

displayed continuously on the oscilloscope.

In the case of erratic voltage changes or voltage peaks

(caused by cracks or soiling) outside the specified

voltage range, the TP sensor is faulty.

Note: Hairline cracks or similar in the sensor may lead

to faults at low temperatures which possibly no longer

occur when the engine is warm.



Electronic differential pressuretransducer / diesel particulatedifferential pressure sensor

E58794

1 2

Diesel particulate filter differential pressure

sensor

1

Electronic differential pressure transducer2

Location

Depending on use:

– as an electronic differential pressure transducer

between the EGR valve and the exhaust manifold,

– as a diesel particulate differential pressure sensor

with a connection upstream of and downstream of

the diesel particulate filter.



Task / function

Detects the differential pressure in the pipe to the EGR

valve or upstream of or downstream of the diesel

particulate filter.

The strain resistances change depending on the pressure

difference. This leads to a change in the signal voltage.

Electronic differential pressure transducer

E58052

There is a throttle point in the pipeline (Venturi).

Depending on the EGR rate, a corresponding pressure

loss occurs at this point. This pressure loss is detected

by the differential pressure sensor and is made available

to the PCM in the form of a voltage signal.

Particulate differential pressure sensor

E59691

The diesel particulate filter provides a certain resistance

to the exhaust gas flow. This leads to a pressure

difference in the exhaust pressure upstream of and

downstream of the diesel particulate filter.



Operating range

Value



–Resistance

–Frequency

Measuring options


YesWDS/IDS DTC


IDS)

++DMM

++Datalogger



required)

– –Powerprobe



Operation of the diesel particulate differential pressure

sensor/electronic differential pressure transducer can

be checked as follows using the hand pump or the

WDS/IDS datalogger:

– select the diesel particulate differential pressure

sensor in the WDS/IDS datalogger.

– remove the hose to the front measuring point

(upstream of the diesel particulate filter) on the diesel

particulate differential pressure sensor;

– connect the hand pump to the connection and set a

pressure at the hand pump (for example, 300 mbar);

– read off the differential pressure on the WDS. The

measured value must correspond to the set value on

the hand pump.



Vehicle speed sensor (VSS)

E58811

1 2

Examples of VSSs

VSS without additional mechanical drive (newer

vehicles without ABS)

1

VSS with additional mechanical drive for the

vehicle-speed display (older vehicles)

2

Location

On the transmission housing (output shaft)


Hall or inductive (relatively old vehicles)

Task / function

The VSS detects the speed of the output shaft in the

transmission.

Depending on the operating principle:

– an alternating voltage is generated (inductive),

– a square-wave signal is generated (Hall).

In proportion to the engine speed

– the voltage and the frequency change (inductive),

– the frequency changes (Hall).

See also OSS (Output Shaft Speed) sensor.

Measurement range

Value

12 V (Hall)

- (inductive)

Supply voltage

Square-wave signal 12 V

(Hall)

Sinusoidal (inductive)


- (Hall)

0.4-0.6 kOhm (inductive)

Resistance

speed-dependentFrequency

Measuring options


YesWDS/IDS DTC


IDS)

+Datalogger

–DMM

+Oscilloscope (breakout


required)

– –Powerprobe





Signal trace of a VSS signal (Hall) at a constant speed

(approx. 30 km/h)

E60150

Signal trace of a VSS signal (inductive) at a constant speed

(approx. 130 km/h)

E60151

The signal trace depends on the installed sensor and the

transmission.

Special features

In the case of newer vehicles with ABS, the vehicle

speed is determined via the wheel speed sensor signals.

The VSS is dispensed with.

In this case, the signal designated with VSS in the

datalogger is calculated by the PCM and/or generated

by the OSS.



Accelerator pedal position (APP) sensor

E47845

Location

Integrated into the accelerator pedal


Sliding-contact potentiometer or inductive

Task / function

The APP sensor determines the current position of the

accelerator pedal.

As a plausibility check, the APP sensor consists of two

to three sensors altogether.

APP sensor with potentiometers

E58187

1

2

Slide tracks for APP1

Shaft with sliding contacts2

When the accelerator pedal is actuated, the shaft with

the sliding contacts is shifted in its position on the slide

tracks.

The slide tracks are designed to provide an evenly

increasing or falling resistance across the entire distance.

The change in resistance leads to a proportional change

in the voltage, which provides information about the

accelerator pedal position.



APP sensor with inductive senders

E58188

2

43

1

A

56

7

V

0

Amperes (amps)A

VoltsV

Rotor1

Electronics2

Primary coil3

Secondary coil4

Analog alternating current5

Generated PWM square-wave signal6

PCM7

The inductive sender functions essentially in a similar

way to a transformer. Initially, the incoming direct

voltage must be converted into alternating voltage.

A rotor is moved in the inductive sender when the

accelerator pedal is actuated. This rotor induces the

alternating voltage between the primary coil and the

secondary coil.

The strength of the induction depends on the position

of the rotor:

– no accelerator-pedal actuation: low induction, i.e.

low amplitude of the AC voltage,

– full accelerator-pedal actuation: high induction, i.e.,

high amplitude of the AC voltage.

To allow the PCM to process the AC voltage signal

issued by the secondary coil, the signal must first be

converted in the sensor electronics.

At present, APP sensors with two inductive senders are

being used in Ford vehicles.

According to the requirements of the engine

management strategy, the signals from the inductive

senders are processes by the electronics in the APP

sensor as follows:

– APP 1 = PWM signal

– APP 2 = analog DC voltage signal

Operating range

APP sensor with potentiometer

Value


Direct voltage: 0-4.5 VSignal type / voltage

dependent on positionResistance

–Frequency


Value


PWM signalSignal type/voltage APP 1

Direct voltage: 0-5 VSignal type/voltage APP 2

–Resistance

–Frequency



APP sensor voltage values on the 2001 Mondeo with

diesel engine

APP 3 (V)APP 2 (V)APP 1 (V)

0.81.44.2Idling

1.11.63.82

1.41.93.43

1.72.33.04

2.02.62.65

2.32.82.26

2.63.21.87

2.93.41.48

3.13.71.09

3.33.90.8WOT

Measuring options

APP sensor with potentiometer


YesWDS/IDS DTC


IDS)

+DMM

++Datalogger



required)

– –Powerprobe





YesWDS/IDS DTC


IDS)

- (APP 1)

++ (APP 2)

DMM

+Datalogger

++ (APP 1)

+ (APP 2)



required)

– –Powerprobe



APP sensor with three potentiometers, idling - wide open

throttle in the datalogger (example: Mondeo with 2.0L

Duratorq-TDCi (Puma) diesel engine)

E58745

To ensure reliable fault detection, the additional sensors

APP 2 and, if necessary, APP 3 may be redundant and/or

can transmit a different voltage signal from APP 1 to

the PCM.

Note: Hairline cracks or similar in the sensor may lead

to faults at low temperatures which possibly no longer




APP sensor with two potentiometers, idling - wide open

throttle in the datalogger (example: Mondeo with 1.8L

Duratec-SCi (MI4))

E59981

Inductive APP sensor (APP 1) during idling in the

oscilloscope (example: C-MAX with 1.6L Duratorq-TDCi

(DV) diesel)

E58746

Idle:

– PWM with short switch-on duration

Inductive APP sensor (APP 1) during WOT in the

oscilloscope (example: C-MAX with 1.6L Duratorq-TDCi

(DV) diesel)

E58747

WOT:

– PWM with long switch-on duration

Special features

APP sensors with sliding-contact potentiometer:

– When making measurements with the sensor, please

note that the sliding-contact potentiometers are

heat-sensitive and in certain circumstances deviations

of up to 10 % may be measured.



Transmission range (TR) sensor

E58054

1

2

Examples of TR (Transmission Range) sensors

TR sensor CFT23 (Hall)1

TR sensor AW81-40 (sliding contact)2

Location

Inner side of the transmission (in the manual selector

valve body) or outer side of the transmission (gearshift

shaft)


Sliding contact, Hall or voltage-coded

Task / function

The TR sensor detects the engaged selector lever

position. At the relevant points, depending on the

operating principle

– an electrical circuit is completed using a contact

switch;

– a digital signal is generated using a Hall sensor;

– a voltage drop is generated using various resistors.

Operating range

Value

Approx. 12 V (sliding contact,

Hall)

Approx. 5 V (voltage-coded)

Reference voltage

Supply voltage

Direct voltage: 12 V (sliding

contact)

Direct voltage: 5 V (voltage-

coded)

Square-wave: 5 V (Hall)


see table *Resistance

–Frequency

* With voltage-coded sensors only

Example: Mondeo with CD4E automatic

transmission

Resistance kOhmSelector Lever Position

Approx. 4.2P (Park)

Approx. 1.44R (Reverse)

Approx. 0.734N

Approx. 0.402D (Drive)

Approx. 0.2112

Approx. 0.0861

Measuring options


YesWDS/IDS DTC


IDS)

+ (sliding contact, voltage-

coded)

- (Hall)

DMM




++Datalogger



required)

– –Powerprobe



It is always possible to test the TR sensor in the

datalogger. The display in the datalogger is adjusted

according to the equipment of the vehicle (eg,

continuously variable transmission, manual gear

selection).

The following tests can therefore be carried out in the

datalogger:

– of the TR sensor,

– of the Select-Shift switch on the selector lever,

– of the Select-Shift switch on the steering wheel,

– of the O/D switch on the selector lever.

TR sensor in the datalogger

E59969

Example: Galaxy with AG5

Display of the individual transmission rangesP - 1

Display for manual gear selectionMAN

The display of the selector-lever position and/or of the

gears for manual gear selection may, depending on the

vehicle equipment, also be shown in the instrument

cluster.

Note for TR sensors with sliding contact: Hairline

cracks or similar in the sensor may lead to faults at low

temperatures which possibly no longer occur when the

engine is warm.

Special features

Even with a correct display in the datalogger, the setting

of the cable between the selector lever and the

transmission should always be carried out using the

special tool and with reference to the workshop

literature.



Remote transmitter.

E41703

3

12

Unlock button1

Luggage compartment unlocking button2

Lock button3

Location

Omitted


Radio or infrared (relatively old vehicles)

Task

When one of the buttons on the remote transmitter is

actuated, the remote transmitter issues a signal.

Depending on the operating principle, the signal from

the remote transmitter is received either by an infrared

receiver or by a radio antenna.

In the case of infrared systems, a visual contact must

exist between the remote transmitter and the receiver.

Systems with a key-free locking system transmit the

relevant radio signal without any actuation of a function

button.

Operating range

Value

Approx. 3/6 VoltsVoltage

Radio signal

Infrared signal


–Resistance

Approx. 433 MHz (radio)

Approx. 10,000 GHz

(infrared)

Frequency

Measuring options


NoWDS/IDS DTC

+ (self-test only)Guided diagnostics (WDS/

IDS)

–DMM

–Datalogger



required)

– –Powerprobe



Radio remote controls can be tested in the self-test of

the GEM (Generic Electronic Module). Instructions for

activating this self-test can be found in the relevant

Service literature.

If the radio range of the transmitter in the radio remote

transmitter decreases constantly, the battery may need

to be replaced. In some systems, this necessity is also

displayed in the vehicle's instrument cluster.



In the Ford Galaxy, the status of the battery can be

checked with a warning indicator in the key. Notes on

this subject can be found in the relevant Owner's

Handbook.

Special features

In the 2006.50 Transit, a rechargeable battery is

integrated in the radio remote control.

The integrated battery is continuously recharged

inductively while the ignition is switched on.



Transmission fluid temperature (TFT)sensor

E58055

1 2

Examples of TFT (Transmission Fluid Temperature)

sensors

Separately installed TFT sensor1

Integral TFT sensor (CFT23)2

Location

Integrated in the automatic transmission housing or in

the transmission control unit.


NTC resistor

Task / function

The TFT sensor measures the current transmission fluid

temperature.


alter depending on the transmission temperature.

Operating range

Value


Direct voltage:

see table


see tableResistance

–Frequency

Values may differ, depending on the transmission


(Kohms)

Temperature

(°C)

4.51 – 4.54860 – 900– 40

4.31 – 4.35253 – 289– 20

3.82 – 3.9289 – 1020

3.0 – 3.235 – 4020

2.0 – 2.215 – 1740

1.2 – 1.47.1 – 8.060

0.6 – 0.93.0 – 4.580

0.4 – 0.51.9 – 2.5100

0.2 – 0.31.0 – 1.3120

Measuring options


Yes, restrictedWDS/IDS DTC


IDS)

+DMM




++Datalogger



required)

– –Powerprobe



Special features

Any TFT sensors integrated in the transmission control

module cannot be replaced separately.



Output shaft speed sensor (OSS)

Input shaft speed sensor (ISS)

Turbine shaft speed sensor (TSS)

The listed sensors are designed to detect speed.

E58059

1 2

Examples of gear-shaft speed sensors

Inductive sensor (4F27E)1

Hall sensor (AW81-40LE)2

Location

The installation location may vary in some transmissions

(automatic transmission, automated manual transmission

and/or continuously variable automatic transmission).

It is located on or in the transmission housing on the

relevant gear shaft.


Inductive or Hall

Task / function

Gear-shaft speed sensors probe a gear or a ring gear on

a gear shaft.

Depending on the operating principle:

– an alternating voltage is generated (inductive),

– a square-wave signal is generated (Hall).

In proportion to the engine speed

– the voltage and the frequency change (inductive),

– the frequency changes (Hall).

See also VSS.

Operating range

Value

Approx. 5 V (Hall)

- (inductive)

Voltage

Square-wave 5 V (Hall)

Sinusoidal, dependent on

speed (inductive)


OSS: 500-900 Ohm *

TSS: 300-800 Ohm *

ISS: 500-600 Ohm *

Resistance


* In inductive sensors only; values may fluctuate depending on the

temperature.

Measuring options


YesWDS/IDS DTC


IDS)

+ (inductive)

- (Hall)

DMM


Lesson 2 – SensorsGear-shaft speed sensors


++Datalogger



required)

– –Powerprobe



NOTE: In the CFT23 automatic transmission, it is not

permissible to take measurements with a multimeter at

the TCM (Transmission Control Module). Failure to

follow this instruction may destroy the TCM.

OSS, TSS (Turbine Shaft Speed) and engine speed in the

datalogger

E59970

1

A B

2

1 2

illustrated: Mondeo with 5F31J

AccelerationA

Fade out timeB

Switching point 1st/2nd gear1

Switching point 2nd/3rd gear2

proportional to the vehicle speedOSS

Engine speedRPM

proportional to the engine speedTSS

Signal trace of an inductive signal during idling on the

oscilloscope

E59984

Example TSS Mondeo with CD4E

Signal trace of an inductive signal at approx. 2,500 rpm

on the oscilloscope

E59985

Example TSS Mondeo with CD4E

The trace of a signal depends on the installed sensor

and the probed gear/ring gear.

Special features

In some transmissions, the OSS is also designated as

VSS.

The signals from the gear-shaft speed sensors are also

used in some transmissions for self-diagnosis purposes.

In the AG5 (Galaxy) and the 5F31J (Mondeo),

intermediate shaft speed sensors are used. These each

have a resistance of approx. 560 Ohm.


Gear-shaft speed sensorsLesson 2 – Sensors

Yaw rate sensor

E59115

1 2

Examples of yaw rate sensors

Separate yaw rate and lateral acceleration sensors

(on a joint holder)

1

Combined yaw rate and lateral acceleration

sensor

2

Location

Central position on vehicle underbody


Piezo or capacitive

Task / function

The yaw rate sensor measures the rotational movement

of the vehicle around the vertical axis. Electronics

integrated in the sensor evaluate the original signal and

generate a digital signal.

Operating range

Value



V


–Resistance


Measuring options


YesWDS/IDS DTC


IDS)

– –DMM

++Datalogger



required)

– –Powerprobe



Only a general function test is possible when checking

the yaw rate sensor using the datalogger. An evaluation

of the signal with WDS/IDS is not possible.

Special features

In some systems, it may be necessary to program or

calibrate the yaw rate sensor with the WDS/IDS after

renewal. In this regard, refer to the instructions in the

current Service Literature.



Glass break sensor

E59542

1

Glass break sensor integrated into the heated rear

window

1

Location

In the rear side window and/or the heated rear window


Ohmic resistance

Task / function

The glass break sensor consists of a resistance loop and

is installed in estate vehicles and saloon cars/vans with

an anti-theft warning system as a separate loop in the

side window or it is integrated into the circuit of the

anti-theft warning system as a component of the heated

rear window.

The resistance increases if the resistance loop is

interrupted.

Operating range

Value


ON/OFFSignal type / voltage

< 0.5 Ohm, wire coil not

interrupted

> 10 kOhm, wire coil

interrupted

Resistance

–Frequency

Measuring options


NoWDS/IDS DTC

+ (self-test only)Guided diagnostics (WDS/

IDS)

++DMM

– –Datalogger



required)

– –Powerprobe





Intrusion sensor

Illustration shows ultrasonic sensor

TIE41628

1

Ultrasonic transceiver1

Location

Depending on the vehicle

– in the B-pillars,

– in the overhead lamp,

– in the headliner,

– on the underbody at the center of the vehicle

(microwave sensor).


Ultrasonic

Microwaves

Task / function

The ultrasonic sensor detects movements within the

vehicle interior and generates an alarm impulse.

Operating range

Value


Alarm impulse, millivoltsSignal type / voltage

–Resistance

–Frequency

Measuring options


Yes *WDS/IDS DTC


IDS)

– –DMM

– –Datalogger



required)

– –Powerprobe



* depending on the system

The intrusion sensors can be checked by switching on

the anti-theft warning system. The tester should be

located in the vehicle.

After an activation phase of approx. 30 seconds, the

tester should move a hand into the beam range of the

respective sensor. This should trigger the alarm.

It is also possible to carry out the test with a window

open. However, only one window should be open a

small distance. An object can then be passed through

this gap into the beam range of the sensor.



Noises (eg, impact screwdrivers) should always be

avoided, because they can impair the function of the

sensor.

Microwave sensor:

– is equipped with a light emitting diode (LED).

– Arm the anti-theft alarm system in order to test the

sensor. The LED must subsequently flash once.

Special features

The intrusion sensors can be deactivated, depending on

the country of use. Notes on this subject can be found

in the relevant Owner's Handbook.

The triggered alarms and the reason for the triggering

(e.g., via the intrusion sensors) are stored in the relevant

module and can be read out using WDS/IDS.



Refrigerant pressure sensor

E59974

Location

On the high pressure side of the A/C (Air Conditioning)

system.



Task / function

The refrigerant pressure switch registers pressure on the

air-conditioning system's high pressure side.


alter depending on the refrigerant pressure.

Also refer to the refrigerant pressure switch.

Operating range

Value



Volt


pressure-sensitive *Resistance

* Not measurable

Refrigerant pressure sensor

Voltage (V)Pressure (bar)

3.9 – 4.0Approx. 30

3.3 – 3.4Approx. 25

2.7 – 2.8Approx. 20

2.1 – 2.2Approx. 15

1.6 – 1.7Approx. 10

1.0 – 1.1Approx. 5

0.5 – 0.7Approx. 1

Measuring options


YesWDS/IDS DTC


IDS)

++DMM

– –Datalogger



required)

– –Powerprobe



Special features

Refrigerant pressure sensors are installed in relatively

new vehicles (eg, Focus 2004.75 1.6L Duratec-16V

(Sigma), Fiesta ST) instead of dual pressure switches.

The linear signal trace permits more precise fan control.



Knock sensor (KS)

E47846

Location

On the engine block under the cylinder head


Piezo

Task / function

The KS (Knock Sensor) records the vibrations

occurring in the cylinder and converts the mechanical

vibrations into electrical voltage signals.

The stronger the vibrations, the higher the frequency

and the alternating voltage.

Operating range

Value

–Voltage

Alternating voltage,

millivolts


Approx. 4.8 MegaohmResistance

4 kHz-18 kHzFrequency

Measuring options


YesWDS/IDS DTC


IDS)

++DMM

– –Datalogger



required)

– –Powerprobe



Connect the multimeter to the KS with the aid of a

breakout box or an adapter cable. Set the multimeter to

the smallest voltage range (mV) for alternating voltage.

When knocking gently against the cylinder block near

to the sensor, it should be possible to measure a voltage.



Signal trace, knock sensor

TIE42093

1

2

A

B 1

2

Normal combustion in engineA

Knocking combustion in engineB

Pressure characteristics in cylinder1

Voltage signal from the KS2

Special features

Depending on the model, one or two knock sensors are

installed in 4-cylinder engines. If one knock sensor is

installed, it is located in the centre of the engine block,

between the 2nd and 3rd cylinders.

If two knock sensors are installed, they are located

between the 1st and 2nd and between the 3rd and 4th

cylinders.

6-cylinder V-engines always have two knock sensors,

each positioned in the centre of a cylinder row.



Force sensor

E59569

1

Parking brake/parking brake actuator module (Teves)

Force sensor1

Location

In the parking brake actuator (electronic parking brake)


Hall

Task

The force sensor (in the electronic parking brake)

measures the force acting on the parking-brake cable.

Operating range

Value

–Voltage


–Resistance

–Frequency

Measuring options


YesWDS/IDS DTC


IDS)

– –DMM

– –Datalogger



required)

– –Powerprobe



The force sensor itself can not be tested, as it is

completely integrated into the parking brake actuator.

If a force sensor is faulty, a complete new parking brake

actuator must be installed.



Fuel pressure sensor.

E30973

Location

In the fuel injection supply manifold of the injection

system



Task / function

The fuel pressure sensor measures the fuel pressure in

the fuel injection supply manifold.


alter depending on the fuel pressure.

Operating range

Value



pressure-sensitive *Resistance

–Frequency

* Not measurable

Setpoint values for the Denso common rail system

Voltage (Volts)Fuel pressure (bar)

Approx. 1.00

Approx. 1.32200

Approx. 2.61000

Approx. 3.561600

Approx. 4.22000

Measuring options


YesWDS/IDS DTC


IDS)

+DMM

++Datalogger



required)

– –Powerprobe



Sample values in diesel common-rail systems

Fuel pressure (bar)Engine speed (rpm)

Approx. 220-270Idling

Approx. 1,400 *

Approx. 1,600 **

Wide open throttle (vehicle

accelerates)

* Common-rail systems, 1st generation.

** Common rail systems, 2nd generation



Fuel pressure at maximum acceleration in 1st gear in the

2.0L Duratorq-TDCi (DW)

E58748

Special features

The fuel pressure sensor must not be replaced separately

during servicing. If a fuel pressure sensor is faulty, the

entire fuel injection supply manifold must be replaced.



Fuel level sensor

E58057

1

2

Connector1

Sender unit for fuel level2

Location

Integrated in the fuel tank in the FPDM (Fuel Pump

Driver Module).


Sliding-contact potentiometer

Task / function

The fuel level sensor records the fuel level in the fuel

tank.

If the fuel level changes, the position of the sliding

contact on the resistance track and so the voltage drop

at the sensor also change.

Operating range

Value


DC voltageSignal type / voltage

see tableResistance

–Frequency

Resistance (Ohm) *Position of fuel level

sensor

> 150Fuel tank empty

Approx. 50-80Fuel tank 50 % full

< 20Fuel tank full

* In the case of relatively old fuel level sensors, two slide paths may

be installed, which work in opposite directions. The resistance values

are therefore reversed.

Measuring options




IDS)

++DMM

+Datalogger



required)

– –Powerprobe






The value displayed by the fuel level sensor in the

instrument cluster can be checked with a self-test of the

instrument cluster. Instructions for this self-test can be

found in the relevant Service literature.

For a more precise test, the tank sensor must be removed

and the resistance of the sliding-contact potentiometer

must be tested directly.

It must be possible to measure a continuous change in

resistance across the entire lever travel.



Fuel temperature sensor

B

A

1

1

2

E85051

System with fuel temperature sensor in the return

line

A

System with fuel temperature sensor at the

high-pressure pump

B

Fuel temperature sensor1

Branch in the fuel return line2

Location

In the fuel return line of the injection system or at the

high-pressure pump


NTC resistor

Task / function

The fuel temperature sensor measures the temperature

of the fuel return.


alter depending on the fuel temperature.

Operating range

Value


DC voltage: 0.1 – 4.9 VSignal type / voltage

temperature-sensitiveResistance

–Frequency

Target resistance values for the Denso common-rail

system

Resistance (kOhms)Temperature (°C)

Approx. 25.4–30

Approx. 15.04–20

Approx. 9.16–10

Approx. 5.740

Approx. 3.7010

Approx. 2.4520

Approx. 1.6630

Approx. 1.1540

Approx. 0.81150

Approx. 0.58460

Approx. 0.42870

Approx. 0.31880

Approx. 0.24090

Approx. 0.184100

Approx. 0.142110

Approx. 0.111120

Voltage range for Bosch common rail system:

• Approx. 0.1 V at 142 °C

• Approx. 4.92 V at –45 °C



Measuring options


YesWDS/IDS DTC


IDS)

++DMM

+Datalogger



required)

– –Powerprobe





Clutch pedal position sensor (vehicleswith hill launch assist)

E70695

Location

At the clutch master cylinder


Inductive

Task / function

Serves to determine the clutch take-up point (pull-away

detection for systems with electronic parking brake).

Operating range

Value


DC voltage: 0.5-4.5 VoltSignal type / voltage

–Resistance

–Frequency

Measuring options


YesWDS/IDS DTC


IDS)

+DMM

++Datalogger



required)

– –Powerprobe



Datalogger signal (bar chart selected)

E87328

Clutch pedal not pressedA

Clutch pedal partially pressed.B

Clutch pedal fully pressed.C

Special features

The sensor can be renewed separately. However,

accessibility to the sensor is restricted when the clutch

master cylinder is installed. For this reason, a special

tool is available for removing and installing the sensor

during repairs (see current service literature).



Crankshaft Position Sensor (CKP)

E58177

21

Examples of CKP sensors

Inductive CKP sensor1

CKP sensor (Hall-effect type)2

Location

Near to the flywheel or the pulley (vibration damper).


Inductive or Hall

Task / function

The CKP sensor probes a ring gear (inductive sensor)

or a magnetic disc (Hall sensor) with a clearly defined

number of teeth or magnetic pole pairs (north/south).

A defined gap is located between the teeth or the

magnetic pole pairs.

The CKP signal is generated according to the speed.

Inductive CKP signal

E58343

(+)1 2

A

6

6

3

4

1 54

7

3

(-)

CKP signal (similar to sinusoidal voltage

characteristics)

A

CKP sensor1

Voltage (Volts)2

Pulses per crankshaft revolution (360 degrees)

*

3

Reference mark (gap on the ring gear)4

Tooth centre5

Tooth interval6

Ring gear (flywheel or serrated disc)7

In vehicles with VP30/VP44 injection pump:

pulses per half crankshaft revolution (180

degrees)

*

The signal frequency and the height of the signal

amplitude increase in proportion to the increasing engine

speed.



CKP signal (Hall)

E58347

3

V5

2

4

1

Magnetic pole pairs (not visible) on magnetic

disc

1

CKP sensor2

Clearance between the pole and the CKP sensor3

Pole gap/reference mark (not visible)4

Square-wave signal from the CKP (Hall) sensor5

In the case of Hall sensors, the frequency of the signal

only increases with the increasing engine speed.

Operating range

Value

- (inductive)

Approx. 5 V (Hall)

Reference voltage

Sinusoidal signal

(inductive)

Square-wave signal

(Hall)


see table (inductive)

- (Hall)

Resistance


Sample values for inductive sensors

Resistance (ohm)Engine code

Approx. 4131.4L/1.6L Duratec-16V (Sigma)

300 – 5801.8L Duratorq-TDCi (Kent) diesel

300 – 5802.0L Duratorq-TDCi (Puma)

Approx. 4601.8L/2.0L Duratec-HE (MI4)

750 – 11001.8L Duratec-SCi (MI4)

approx. 4002.0L Zetec-E (Zetec)

Measuring options


YesWDS/IDS DTC


IDS)

+ (inductive)

- (Hall)

DMM

–Datalogger



required)

– –Powerprobe



Special features

The starter motor speed is significant for inductive

sensors.

In order to obtain a reliable signal for further processing

in the PCM, a specific speed and consequently a specific

minimum voltage must be attained during the start-up



process. Moreover, the minimum voltage from which

the CKP signal will be accepted by the PCM software

to start the engine depends on the strategy.

Example:

– 1.8L Duratorq DI: approx. 0.8 to 1 V

– Delphi common-rail systems: approx. 2.9 to 3.4 V

The correct setting of the air gap between the sensor

and the sensor ring and the installation location of the

sensor are extremely important. Minor deviations may

cause the engine not to start.

Soiling (eg, oil or corrosion residue) between the sensor

ring and the sensor may cause the engine not to start or

to run irregularly.

If the engine starts and runs smoothly, the signal is

correct.



Engine coolant temperature sensor(ECT) and cylinder head temperaturesensor (CHT)

E58183

1 2

Examples CHT (Cylinder Head Temperature)/ECT

sensors

CHT sensor1

ECT sensor2

Location

ECT sensor: in the small coolant circuit of the engine

CHT sensor: on the cylinder head


NTC resistor

Task / function

The ECT/CHT sensor measures the current engine

coolant or cylinder head temperature.


alter depending on the engine coolant or cylinder head

temperature.

Operating range

Value


Direct voltage: see tableSignal type / voltage

see tableResistance

–Frequency

NOTE: Values for CHT sensors are output differently

in datalogger measurements with WDS/IDS after the

"voltage jump" (see Special features).

ECT/CHT sensor setpoint values in Visteon systems


(Kohms)

Temperature

(°C)

4.51 – 4.54860 – 900–40

4.46 – 4.49501 – 645–30

4.31 – 4.35253 – 289–20

4.17 – 4.23170 – 196–10

3.82 – 3.9289.0 – 1020

3.5 – 3.762.0 – 70.010

3.0 – 3.235.0 – 40.020

2.6 – 2.825.0 – 28.030

2.0 – 2.215.0 – 17.040

1.7 – 1.911.0 – 13.050

1.2 – 1.47.1 – 8.060

0.9 – 1.25.0 – 6.270

0.6 – 0.93.0 – 4.580

0.5 – 0.72.4 – 3.590

0.4 – 0.51.9 – 2.5100

0.3 – 0.41.5 – 1.7110

0.2 – 0.31.0 – 1.3120



ECT/CHT sensor setpoint values on the 1.4L

Duratorq-TDCi (DV) Diesel, 1.6L Duratorq-TDCi

(DV) Diesel and 2.0L Duratorq-TDCi (DW) Diesel

engines


(kOhms)

Temperature

(°C)

–88.500 ± 5.99 %–30

–48.535 ± 5.14 %–20

–27.665 ± 4.43 %–10

–16.325 ± 3.74 %0

–9.950 ± 3.12 %10

Approx. 3.636.245 ± 2.60 %20

Approx. 3.234.029 ± 2.37 %30

Approx. 2.812.664 ± 2.03 %40

Approx. 2.251.802 ± 1.78 %50

Approx. 1.811.244 ± 1.54 %60

Approx. 1.420.876 ± 1.,32 %70

Approx. 1.110.629 ± 1.13 %80

Approx. 0.880.459 ± 1.05 %90

–0.340 ± 0.88 %100

–0.256 ± 1.20 %110

–0.195 ± 1.56 %120

ECT/CHT sensor setpoint values for 1.8L

Duratec-SCi (MI4) engine

Voltage (V) *Resistance

(Kohms)

Temperature

(°C)

Approx. 4.7462.0 – 70.010

Approx. 4.5835.0 – 40.020

Approx. 4.3725.0 – 28.030

Approx. 4.1215.0 – 17.040

Approx. 3.819.0 – 13.050

Voltage (V) *Resistance

(Kohms)

Temperature

(°C)

Approx. 3.467.1 – 8.060

Approx. 2.975.0 – 6.270

Approx. 2.663.0 – 4.580

Approx. 2.282.4 – 3.590

* The voltage values displayed in the WDS/IDS datalogger deviate

significantly from the characteristic curve, so they are not suitable

for a specific measurement. To measure the voltage values, connect

the DMM to the ECT sensor with a suitable adapter cable.

Measuring options


YesWDS/IDS DTC


IDS)

++Datalogger

++DMM



required)

– –Powerprobe



Special features CHT sensor

At high temperatures, the resolution of the CHT sensor

is not sufficient to cover the entire temperature range

adequately with high precision.

Therefore the temperature curve is shifted by activating

a second resistor "in the PCM".



The activation/deactivation point of this second resistor

depends on the relevant engine-management strategy.

The activation and deactivation points can be offset to

each other (hysteresis) to prevent continual activation

and deactivation during continuous engine operation in

the vicinity of the switching point.

Examples:

– Visteon systems (petrol engines):

– Activation/deactivation point: 95 °C

– Visteon systems (diesel):

– Activation point: 78 °C

– Deactivation point: 62 °C

– Siemens systems (diesel):

– Activation point: 85 °C

– Deactivation point: 80 °C



General

TIE42064

The illustration shows a planar dual-point HO2S

Location

In the exhaust branch upstream of and downstream of

the three-way catalytic converter, depending on the

function.

Note: In vehicles with direct petrol injection, a third

HO2S is located downstream of the NOx catalytic

converter.


Galvanic element

Task / function

The HO2S measures the residual oxygen content in the

exhaust gas. This measuring signal permits the

classification of whether a rich or a lean mixture is being

combusted.

Note: The oxygen sensors used at Ford contain a heat

resistor to guarantee reliable function even in low

exhaust temperatures. The ground connection is made

via the connector of the respective PCM. The power

supply to the oxygen sensor merely supplies the heat

resistor.


Oxygen sensors (HO2S)Lesson 2 – Sensors

Dual-point HO2S (NTK)

Layout and operation

E58190

AB

B

C+ -

2 1

41

Exhaust gas flow in the exhaust manifoldA

Ambient air, exteriorB

Sensor voltageC

Solid-state electrolyte made of zirconium dioxide

(ZrO2)

1

Platinum electrode, air side (21 % oxygen)2

Platinum electrode, exhaust side (remaining

oxygen)

3

Exhaust gas flow4

The sensor element consists of a ceramic holder

(zirconium dioxide) which is covered on the interior

and exterior with electrodes made of a gas-permeable

platinum layer. The sensor extends into the exhaust gas

flow and is surrounded by low-oxygen exhaust gases

on the outside. The ambient air with an oxygen content

of 21 % reaches the interior.

The sensor element can conduct oxygen ions as from a

temperature of over 300 °C.

E58191

900800700600500400300200100

0

0,9 1,0 1,1

B

A

C

ED

F

Operating range of the dual-point HO2S

Voltage in mVA

Sensor signal in mVB

Lambda window (ideal mixture)C

rich mixtureD

lean mixtureE

OxygenF

Burning a lean mixture leads to a high residual oxygen

content, while burning a rich mixture leads to a low

residual oxygen content.

This is detected by the dual-point HO2S based on the

type of ionic migration.

The ionic migration causes a dramatic increase or

reduction in the sensor voltage. This voltage jump is

used for lambda control purposes.

A voltage potential of 0.1 volts (lean mixture) to 0.9

volts (rich mixture) is generated according to the

existing residual air content in the exhaust gas.



Operating range

Value

Approx. 12 VHeating voltage

Pulsed DC voltage: 0.1 –

0.9 V


Approx. 5 Ohm *Resistance

–Frequency

* Oxygen sensor heating at +20 °C

Measuring options


YesWDS/IDS DTC

++Guided diagnostics

(WDS/IDS)

++Datalogger

–DMM



required)

– –Powerprobe



The illustration shows signals from the upstream (O2S11)

and the downstream (O2S12) HO2S in the 1.8L Zetec-E

in the Focus during idling.

E59760

NOTE: Thanks to the exhaust gas conversion in the

three-way catalytic converter, the measured vibrations

in the downstream HO2S are low (prerequisite: the

three-way catalytic converter is working efficiently).

The function of the HO2S can be tested using an HO2S

tester. Please observe the manufacturer's operating

instructions for the HO2S tester.

Measuring prerequisite:

– engine at operating temperature.

Note: The measurement must be made with the engine

running.

If no HO2S tester is available, the specified voltage

values can also be measured with a conventional

multimeter.

For this purpose, connect the PCM, the wiring harness

and the testing device using a suitable adapter cable.



Planar dual-point HO2S


The planar dual-point HO2S (Bosch) is an enhancement

of the dual-point HO2S (NTK). However, it works

according to the same jump characteristic as the

dual-point HO2S (NTK).

"Planar" in this HO2S means that planar films form the

solid-state electrolyte. The planar sensor element has

the shape of an elongated thin plate with a rectangular

cross-section.

TIE42099

4

1

2

3

Basic structure of the planar dual-point HO2S

Exhaust gas1

Sensor voltage2

Heating voltage3

Reference air duct4

The core of this HO2S consists of a special planar

ceramic body and a sensor element. The outer electrode

side extends into the exhaust gas flow, and the inner

electrode side is connected to the reference air duct

(external air).

The difference in the oxygen content between the outer

and inner electrodes can be measured as a voltage

difference.

Operating range

Value

Approx. 11-14 VHeating voltage

Pulsed DC voltage: 0.1 –

0.9 V


7 – 15 Ohm *Resistance

–Frequency


Measuring options


YesWDS/IDS DTC


IDS)

++Datalogger

+ (analog display)DMM



required)

– –Powerprobe



The function of the HO2S can be tested using an HO2S

tester. Please observe the manufacturer's operating

instructions for the HO2S tester.

Measuring prerequisite:

– engine at operating temperature.

Note: The measurement must be made with the engine

running.



If no HO2S tester is available, the specified voltage

values can also be measured with a conventional

multimeter.

For this purpose, connect the PCM, the wiring harness

and the testing device using a suitable adapter cable.



Planar broadband HO2S

TIE42061


The planar broadband HO2S allows measurements of

the exhaust gas which deviates from the stochiometric

ratio (lambda = 1).

The measuring range extends from lambda 0.7 to 2.8,

whereby the broadband HO2S emits a clear, constant

pump current signal.

With these properties, the broadband HO2S can not only

be used in petrol engine-management systems with

dual-point control (lambda = 1), but even more so in

petrol engine-management systems with lean concepts

(lambda > 1).

Example:

– Planar broadband HO2S for direct petrol injection

TIE42098

5

7

9

1 2

8 6

4

3

Nernst concentration cell1

Oxygen pump cell2

Measuring area3

Pump current4

Regulating switch5

Reference voltage6

Heater7

Heating voltage8

Reference air duct9

The broadband HO2S consists of a Nernst concentration

cell and an oxygen pump cell, which transports the

oxygen ions.

Between the oxygen pump cell and the Nernst measuring

electrode, there is a diffusion gap which acts as the

measuring area and is connected to the exhaust gas.

The Nernst concentration cell is connected via a duct

to the ambient reference air and the measuring area and

detects the mixture composition in the measuring area.

A concentration of lambda = 1 is set in the measuring

area using the oxygen ion flow. This is done by applying

a reference voltage which results in a pump current.

In the case of lean exhaust gas, the oxygen pump cell

is activated so that oxygen ions are pumped out of the

measuring area. This is detected by the regulating

switch, so that the flow can move (positive direction).



In the case of rich exhaust gas, the direction of flow is

reversed so that the cell pumps oxygen ions into the

measuring area. The regulating switch detects this, so

the flow is reversed (negative direction).

TIE42062

1

2

Pump current as a function of the excess air factor

lambda of the exhaust gas.

Pump current in mAIp

positive pump current1

negative pump current2

The pump current represents a direct measurement of

the mixture composition. With lambda 1 (14.7 kg air/1

kg fuel), the pump current is 0 mA.

The characteristic curve of the broadband HO2S is

constant (linear), without a lambda jump.

Operating range

Value

Approx. 11-14 VHeating voltage

Analog direct current

(mA)

Signal current/type

2.4 – 4.1 Ohm*Resistance

–Frequency


Values for the 1.8L Duratec-SCi (at operating

temperature)

Pump current (mA)Operating mode

Approx. 1.0 – 2.0Shift operation (idling)

Approx. 0Homogeneous operation

(approx. 4,000 rpm)

Measuring options


YesWDS/IDS DTC


IDS)

++DMM

++Datalogger

–Oscilloscope

– –Powerprobe



Note for vehicles with 1.8L Duratec-SCi (MI4):

• Only the lambda value of the broadband HO2S is

indicated in the datalogger.

• In order to display the pump current, "Mode 1

Powertrain" must be called up in "OBD Mode". The

relevant PID must then be selected.



Steering wheel rotation sensor

E58053

3

1 2

Examples of steering wheel rotation sensor

Magneto-resistive steering wheel rotation sensor,

Mondeo 2001

1

Opto-electronic steering wheel rotation sensor

with integrated spring, Focus 1999

2

Opto-electronic steering wheel rotation sensor,

Ford Focus 2004.75

3

Location

At the steering column and/or directly behind the

steering wheel


Opto-electronic or magneto-resistive

Task / function

The steering wheel rotation sensor measures the rotation

of the steering wheel.

A digital signal is generated via integrated evaluation

electronics according to the movement of the steering

wheel.

In terms of the relative steering angle, the sensor

measures only changes in the steering wheel rotation.

The straight ahead position of the steering is not defined

in the sensor.

In the case of absolute steering angle detection, the

sensor generates a specific signal for every steering

wheel position. The straight ahead position of the

steering is therefore defined in the sensor.

Operating range

Value



V


–Resistance


Measuring options


YesWDS/IDS DTC


IDS)

– –DMM

++ (restricted)Datalogger



required)

– –Powerprobe



Steering wheel rotation sensors are monitored

continuously by the ABS/stability assist module.



Signal trace of the steering wheel rotation sensor in the

datalogger

1 1

2

3

E58752

Steering wheel in straight ahead position1

One steering wheel revolution to the right2

One steering wheel revolution to the left3

In terms of the representation of the signal in the

datalogger, please not that in some cases it may not be

possible to display the measuring range for the entire

steering wheel rotation (stop to stop).

However, for checking purposes, one steering wheel

revolution in each direction will suffice, because any

possible error will simply be repeated.

Opto-electronic steering wheel rotation sensor

E59706

1

4

3 2

Segment disc (engaged in steering spindle)1

Photoelectric barrier2

Evaluation electronics3


The opto-electronic steering wheel rotation sensors use

photoelectric barriers for non-contacting pickup of the

segment disc which is firmly attached to the steering

column shaft.



Magneto-resistive steering wheel rotation sensor

E53338

1

2

4 4

5

6

2

3 3

Drive wheel (engaged in steering spindle)1

Gearwheel2

Permanent magnet3

Magneto-resistive resistance4

Evaluation electronics5


Magneto-resistive steering wheel rotation sensors consist

of two permanent magnets, each of which are connected

to the steering column shaft via a spur gear mechanism.

The gear ratio of both mechanisms is different, which

means that for each steering wheel position the magnets

are positioned individually to each other.

Special features

In some systems, it is necessary to program or calibrate

the steering wheel rotation sensor with the WDS/IDS

after renewal. In this regard, refer to the instructions in

the current Service Literature.

It is possible to carry out a function test at the same time

as setting.

Test of steering wheel rotation sensor in guided diagnostics

E59707



Light sensor

2

1

3E40968

Light/rain sensor unit

Lens1

Close-range light sensor2

Long-range light sensor3

Location

The light sensor for the autolamps is integrated in a unit

with the rain sensor for the rain sensing wipers, which

is attached behind the windshield close to the interior

rear view mirror in the wiping area of the windshield

wipers.


Photovoltaic effect

Task / function

The light sensor consists of the following three main

components:

– Close-range light sensor

– Long-range light sensor

– Lens.

The close-range light sensor measures the light intensity

in the immediate vicinity of the windshield.

The long-range light sensor determines the light

intensity in front of the vehicle.

If both the close-range and long-range light sensors

signal a sudden drop in the light intensity at the same

time, an algorithm in the autolamp module (Mondeo

2001 (06/2003-)) or the GEM (all other vehicles) is used

to transmit a digital code in the form of a frequency.

Operating range

Value


Digital codeSignal type / voltage

–Resistance

–Frequency

Measuring options


Yes (except Mondeo)WDS/IDS DTC

– – *Guided diagnostics (WDS/

IDS)

–DMM

– –Datalogger



required)

– –Powerprobe



* In the case of a faulty light-sensor signal, the low beam shines

constantly when the "autolamps" function is switched on.

Note: The sensor is able to distinguish between daylight

and artificial light.



The light sensor cannot be diagnosed.

Special features

If the light sensor fails, the headlamps can still be used

in manual mode.

In the Mondeo 2001 (06/2003-), a separate module is

installed to control the autolamps. It is located under

the instrument panel (driver side).

In the Focus C-MAX (06/2003-) and the Focus 2004.75

(07/2004-), control of the autolamps is via the GEM.



Mass air flow sensor (MAF)

E43235

1

2

Location

In the intake tract, downstream of the air cleaner.


Hot wire principle or hot film principle

Task / function

The MAF sensor measures the mass of the air flowing

into the engine.

Function of the hot wire MAF sensor.

E58184

21

3

Air temperature sensor1

Hot wire2

Bypass duct3

The intaken mass air flows through a Venturi nozzle

located in the housing of the MAF sensor. The vacuum

resulting from this nozzle effect sucks a specific volume

of air through a bypass duct.

A hot wire and a temperature compensation resistor are

located in this bypass duct.

The air temperature sensor measures the temperature

of the intake air flowing through, which cools off the

heated hot wire.

A regulating switch supplies the heating current in such

a way that the hot wire attains a constant excess

temperature in comparison to the intake air.

This measuring principle takes into account the air

density to the correct degree, because it partly

determines the extent of the heat loss from the hot wire

to the air.

The heating current is therefore a measurement for the

mass air flow. The control electronics in the sensor use

the heating current to generate a voltage signal

proportional to the mass air flow, which is then provided

as an input voltage for the PCM.



The following applies:

– small intake of mass air: low voltage (approx. 0.5

V),

– considerable intake of mass air: high voltage (close

to 5 V).

Function of the hot film MAF sensor.

E58185

1

2

4 3

5 6 5

Case1

Case cover2

Control electronics3

Sensor element4

Sensor measuring cell5

Heating zone6

Note: Depending on the engine-management strategy,

the hot film MAF sensor may be designed as an analog

or a digital sensor.

The hot film MAF sensor is able to detect the return

flow of the intaken air.

A sensor measuring cell is heated electrically on the

integrated chip and then cooled by the air flowing

through. The control electronics supply the heating

current in such a way that the chip attains a constant

excess temperature in comparison to the intake air.

Both the mass air flow and the direction of flow can be

derived from this heating current (given in the form of

a signal voltage). As a result, a precise calculation of

the mass air is possible, even with strongly pulsating

air flows.

The direction of flow can be detected from the nature

of the cooling on both sensor measuring cells.

Operating range

Value

Approx. 12 V

Approx. 5 V

Supply voltage (some vari-

ants)

Reference voltage


V

PWM square-wave

signal: 0/12 V


–Resistance

–Frequency



Measuring options


Yes (with an electrical

malfunction)

No (with soiling)

WDS/IDS DTC


IDS)

++ (analog signal)

- (PWM signal)

DMM

++Datalogger

- (analog signal)

++ (PWM signal)



required)

– –Powerprobe



Note: The MAF signal output in the WDS/IDS

datalogger differs depending on the vehicle version.

The output may be specified in Volts (V) or in

grams/stroke (g/s).

The output value from the MAF sensor depends on the

design of the intake system and the displacement of the

vehicle.

Signal trace of the analog MAF sensor at maximum

acceleration in 3rd gear in the 1.8L Zetec-E in the Focus

(datalogger signal)

E59038

With the wide open throttle measurement in 3rd gear,

the MAF value should be over 4 V.

Signal trace of the analog MAF sensor at maximum

acceleration in 3rd gear in the 2.2L Duratorq-TDCi

(Puma) in the Mondeo (datalogger signal)

E85327

With the wide open throttle measurement in 3rd gear,

the MAF value should be over 4 V.



Signal trace of the digital MAF sensor at maximum

acceleration in 3rd gear in the 1.6L Duratorq-TDCi (DV)

diesel and 2.0L Duratorq-TDCi (DW) in the Focus

(datalogger signal)

E59039

Sample values at maximum acceleration in 3rd gear:

– 1.6L Duratorq-TDCi in the Focus C-MAX: approx.

120 g/s

– 2.0L Duratorq-TDCi in the Ford Focus C-MAX:

approx. 150 g/s

Digital MAF sensor

The illustration shows the signal of a digital MAF sensor

in a diesel engine when idling (oscilloscope signal)

E58355

NOTE: The signal change in the centre represents the

intake manifold pulsation.

The PWM signal changes with the increasing speed and

increasing mass air flow. Moreover, the mass air flow

and so the signal from the sensor depend on the design

of the intake tract.

Special features

An IAT sensor is integrated in newer MAF sensors.

This essentially helps to correct the MAF signal. This

ensures a more precise measurement of the mass air.

The physical operating principle and the testing

possibilities are the same as those for the separate IAT

sensor.

In some vehicles, it is necessary to carry out a parameter

reset in the control module using the WDS/IDS after

installing a new MAF sensor. Instructions for this can

be found in the current Service literature.



Air temperature sensor, air outlettemperature sensor

E58065

1

1

1

2

Examples of air temperature/air outlet temperature

sensors

Sensor element1

Interior temperature sensor with integrated fan2

Location

On the instrument panel and/or at the air vents


NTC resistor

Task / function

Air outlet temperature sensors measure the temperature

at the air vents, and the air temperature sensor measures

the interior temperature in the vehicle.


alter depending on the air temperature.

Operating range

Value



see tableResistance

–Frequency

Values not applicable to the Galaxy

Resistance (kOhm) *Temperature (°C)

28 – 325

22 – 2410

12 – 1420

6 – 830

< 540

* Measured in the water bath Values may differ, depending on the

installation location.

Measuring options




IDS)

+DMM

++Datalogger



required)

– –Powerprobe





Depending on the vehicle and the equipment, several

sensors may be installed in the footwell air vents, the

windshield and the center vents (in the instrument

panel).

These can be depicted individually in the datalogger.

Please ensure that the preset measuring range is set to

the ideal values for the diagnosis (0-50 °C).

Signal trace of the air-conditioning temperature sensors

in the datalogger given a temperature change.

E58749

1

2

3

Display with temperature change

Air outlet temperature, centre vents1

Air outlet temperature, footwell2

Passenger compartment temperature3

The displayed values must change accordingly when

the temperature or the air flaps change. The displayed

value can be compared simultaneously with a

conventional thermometer. To do so, the thermometer

must be held in the relevant air flow.

Special features

In interior temperature sensors, an additional fan is often

used which sucks the air to be measured out of the

vehicle interior to ensure an optimal measuring result.

This can also be depicted in the datalogger (display in

Hertz (Hz)). If this fan fails, the sensor value displayed

in the datalogger may deviate from the actual interior

temperature.



Inclination sensor

E58058

1

1

A B

Examples of inclination sensors

Inductive (shown: Focus 1999)A

HallB

Lever arm1

Location

One sensor at both the front and rear axles (vehicles

with automatic headlamp levelling)


Hall or inductive

Task / function

The inclination sensor measures the relative vehicle

height compared to a preset value.

A voltage signal is generated via the integrated

evaluation electronics according to the inclination of

the vehicle and the resulting change in the lever arm.

Operating range

Value

4.8 – 5.2 V

12 V *

Supply voltage

Direct voltage: 0.5-4.5 V

Direct voltage: 1.8-9.4 V

*


–Resistance

–Frequency

* Applies only to Focus 1999, front sensor; see Special features.

Measuring options


YesWDS/IDS DTC


IDS)

+DMM

++Datalogger



required)

– –Powerprobe





Signal trace in the datalogger given repeated changes in

the vehicle height (brief rocking)

E58754

In some systems, the signal values from the sensors may

be displayed differently in the datalogger (Volts, degrees

or percentage).

Signal trace across the entire measuring range in the

datalogger (with lever arm removed)

E58753

For a precise test of the sensor, the lever arm of the

sensor should be removed and the entire lever travel of

the sensor should be displayed in the datalogger.

Please note that, in the case of fully sprung vehicles,

the sensor values may lie outside the measuring range

and a test is only possible to a limited degree.

Special features

The data from the front and rear sensors aid the

calculation of the inclination of the vehicle and so

provide a reference variable for correcting the range of

the headlamps.

A change in the signal does not necessarily lead to a

direct adjustment of the range, because the systems work

with different reaction times and algorithms.

In the Focus 1999, please note that a control module is

integrated in the front sensor. This module generates a

voltage signal between 1.8 and 9.4 Volts which directly

activates the adjustment motors for the headlamp

levelling.

In the case of vehicles with subsequently adjusted

vehicle height (eg, lowering of the chassis), it may be

necessary to adjust the fastening points of the sensors

and/or the lever arms accordingly.

When working on inclination sensors, please ensure that

the installation location is correct, because otherwise

the correct function of the sensors can not be guaranteed.

In some systems, it may be necessary to program or

calibrate the inclination sensor after renewal. In this

regard, refer to the instructions in the current Service

Literature.

Inclination sensors are also referred to as headlamp

levelling sensors or vehicle level sensors.



Camshaft Position Sensor (CMP)

E58181

1 2

3

Examples of CMP sensors

Inductive CMP sensor (example from the 1.8L

Duratec-HE (MI4))

1

CMP sensor (Hall principle) (example from the

1.8L Duratec-SCi (MI4))

2

CMP sensor (Hall effect) (example from the 1.4L

Duratorq-TDCi (DV) diesel)

3

Location

On the cylinder head, depending on the position of the

phase sensor. Phase sensors may be:

– reference cams on the camshaft,

– Phase sensing at the camshaft timing belt pulley.


Hall or inductive

Task / function

Supports the detection of cylinder 1 and so the definition

of the injection sequence.

The CMP sensor monitors one (or several) reference

cams on the camshaft or the phase sensor on the

camshaft pulley. The number of signals and the signal

intervals depend on the type of injection and the relevant

engine-management strategy.

Operating range

Value

- (inductive)

Approx. 5 V/12 V (Hall)

Voltage


Square-wave (Hall)


200-900 Ohm (inductive)

- (Hall)

Resistance


Measuring options


Not in all systems

(depends on software)

WDS/IDS DTC


IDS)

+ (inductive)

- (Hall)

DMM

+Datalogger



required)

– –Powerprobe





Inductive signal with sequential intake manifold injection

2.5L Duratec-VE during idling (oscilloscope)

E58339

In the inductiveCMP sensor, the signal frequency and

the signal amplitude increase in proportion to the

increasing camshaft speed.

As a result, the signal can only be provided reliably as

from a certain camshaft speed (engine speed).

This type of CMP sensors is primarily used in sequential

petrol intake manifold injection.

The sequential injection is carried out as from an engine

speed of 400-600 rpm.

In these systems, the detection of cylinder 1 is supported

by a reference cam, which passes the CMP sensor every

working cycle (two crankshaft revolutions).

Hall signal in direct petrol injection 1.8L Duratec-Sci

during idling (oscilloscope)

E59133

In the case of Hall sensors, the square-wave signal

voltage depends on the speed. In these sensors, the

frequency of the signal only changes with the

falling/increasing engine speed.

Hall CMP sensors are mainly used in engines with

direct fuel injection.

The reason for this is the high priority of the clear and

rapid definition of the injection sequence even during

the start process with relatively low starter speeds

(between 250-300 rpm in common-rail diesel engines).

Depending on the engine-management strategy, one or

several cams/phases can be implemented for detecting

the cylinders.

The signal sequence depends on the arrangement of the

reference cam(s) (in relation to the CKP signal) and the

engine-management strategy.



Oil level/temperature sensor

E85070

Apertures to the oil level measuring section1


Heating wire3

Temperature sensor4

Location

In the lower part of the cylinder block, near

the oil dipstick


Oil level sensor: heated wire principle

Temperature sensor: NTC

Task / function

Serves to calculate the oil level and the oil condition.

Operating range

Value

–(heating wire)

Approx. 5 V (temperature

sensor)

Reference voltage


see table belowResistance

–Frequency

NOTE: The heating wire is only activated briefly by

the PCM when certain conditions are fulfilled. Current

or voltage measurement is therefore not possible.

Heating wire setpoint values

Resistance (ohms)Temperature (°C)

Approx. 7.9–30

Approx. 9.820

Approx. 14.8160

Temperature sensor setpoint values

Resistance (ohms)Temperature (°C)

80429 – 106834–40

41895 – 54306–30

22717 – 28796–20

7442 – 90780

2772 – 326920

1151 – 132040

526 – 58860

261 – 28580

139 – 149100

78 – 83120

45 – 50140

27 – 32160



Measuring options


YesWDS/IDS DTC


IDS)

++DMM

– –Datalogger



required)

– –Powerprobe





Position sensor - gearshift actuator

E59539

1

2

3

Transit automated manual transmission

Position sensor - shift cylinder1

Position sensor - selection cylinder2

Position sensor - reverse gear3

Location

On the housing of the gearshift actuator (Transit with

automated manual transmission)


Inductive (permanent magnet with three coils)

Task / function

The gearshift actuator position sensor detects the

movement of the shift or the selection cylinder. A

voltage is applied to the primary coil. The movement

of the magnets then induces a suitably different voltage

in the secondary coils.

Operating range

Value



see tableResistance

–Frequency

Resistance values for gearshift actuator position

sensor

Resistance (ohm)Coil

Approx. 68Primary

Approx. 32Secondary I

Approx. 32Secondary II

Measuring options


YesWDS/IDS DTC


IDS)

+DMM

++Datalogger



required)

– –Powerprobe





Gearshift actuator position sensor in the datalogger

E58870

Selector Lever PositionA

Range selectedB

The signal of the gearshift actuator position sensor can

be displayed in the datalogger. The displayed

transmission-range position must correspond to the gear

engaged by the transmission.

Special features

The gearshift actuator position sensor is also referred

to as a selector and shift travel sensor.



Wheel speed sensor

E52529

Location

On each of the wheel hubs of the front and rear wheels


Inductive (passive) or magneto-resistive (active)

Task / function

Wheel speed sensors measure the speed of the individual

wheels.

According to the operating principle, an AC voltage

signal (inductive) or a PWM square-wave signal with

constant frequency (magneto-resistive) is generated.

Inductive senor:

– The signal frequency and the signal amplitude

increase in proportion to the increasing wheel speed.

Magneto-resistive sensor

– Only the frequency of the signal increases

proportionally to the increasing engine speed.

Operating range

Value

- (inductive)

11.3 – 11.5 V (magneto-resistive)

Supply voltage


PWM square-wave signal 7-14

mA (magneto-resistive)

Signal type /

voltage

0.9-1.4 kOhm (inductive)

- (magneto-resistive)

Resistance

speed-dependent (inductive)

constant (magneto-resistive)

Frequency

Measuring options


YesWDS/IDS DTC

++Guided diagnostics

(WDS/IDS)

+ (inductive)


DMM

++Datalogger

+ (inductive)




required)

– –Powerprobe



A bar-chart format is recommended for representation

in the datalogger. In the case of driving straight ahead,

all four sensor signals should be at the same height.



All four wheel speed sensor signals in order (datalogger)

E58768

If one or several of the signals deviate significantly,

there is probably a fault in that sensor circuit.

Failure of a wheel speed sensor signal (datalogger)

E58751

Active wheel speed sensor

Since the end of the 90s, so-called active

(magneto-resistive) wheel speed sensors have been used

more frequently. The advantage over inductive sensors

is that the active sensors are able to pick up wheel speeds

from a standstill, which is of importance on traction

control systems at the moment the vehicle pulls away,

for example.

E58801

The wheel speed sensor usually consists of two

magneto-resistive resistors that are connected together

by means of two constant resistances in the form of a

bridge (Wheatstone bridge).

This type of connection helps to compensate for ageing

and temperature influences that affect the wheel speed

sensor over the service life of the vehicle.

A wheel speed sensor ring, consisting of alternately

opposing permanent magnets, passes over the bridge.

The wheel speed sensor ring is fixed permanently to the

wheel hub, i.e. with the inner ring of the wheel bearing,

and turns at the same speed as the wheel.

Integrated in the sensor are evaluation electronics that

convert the sinusoidal signal resulting from the

measurement into a PWM signal with constant

frequency.

The sensor requires a supply voltage for operation and

features two electrical connections.

The sensor signal results from the current that flows

through the sensor. A high current (approx. 14 mA) is

interpreted by the ABS/stability assist module as a high

signal, and a low current (approx. 7 mA) is interpreted

as a low signal.



Passive wheel speed sensor

In order for the ABS/stability assist module to process

the sensor signal of the passive wheel speed sensor

(inductive) effectively, a sufficient amplitude strength

is required.

This means that a signal which can be processed is only

available from a minimum speed (approx. 5-7 km/h

depending on the system).

Special features

Both the active and the passive wheel speed sensors are

wear-free.

However, due to the use of permanent magnets, metallic

particles such as abrasion particles from the braking

system could build up on the sensors and/or wheel speed

sensor rings during the service life of the vehicle.

These abrasion particles can impair the function of the

sensor. For this reason, it is important to check and

ensure the cleanliness of the wheel speed sensors and

the wheel speed sensor rings carefully if sensor-related

malfunctions are encountered.



Rain sensor

E40970

1

2

34

Raindrop1

Light emitting diode (LED) (infrared sensor)2

Lens3

Photodiode (infrared receiver)4

Location

The rain sensor is integrated in a unit with the light

sensor, which is located behind the windshield close to

the interior mirror in the wiping area of the windshield

wipers.


Infrared

Task / function

The rain sensor measures the volume of precipitation

falling on the windshield.

When a defined precipitation volume is measured on

the windshield by the sensor, an algorithm in the

autolamp module (Mondeo 2001 (06/2003-)) or the

GEM (all other vehicles) is used to transmit a digital

code in the form of a frequency.

The transmitter diodes (light emitting diodes) emit an

infrared light, which is directed through the windscreen

and is reflected at its outer surface. Receiver diodes

(photodiodes) receive the reflected light.

The light is deliberately guided at a specific angle so

that the light at the outside of the windshield (glass-air

transition) is reflected 100 %.

If the windshield surface is dry, the infrared light

reaches the receiver diode at almost full intensity (total

reflection).

However, if the windshield is wet, the infrared light is

diverted by the water drops and only partially reaches

the receiver diode (partial reflection).

The receive volume of light depends on the rain

intensity, because raindrops disrupt the reflection at the

glass surface to a certain extent. As the windshield

surface becomes increasingly wet, the percentage of

light reflection decreases.

The proportion of the reflected volume of light acts as

a control variable for the interval time. As a result, the

rain sensor controls the speed of the windshield wiper

in accordance with the "measured" quantity of rain.

Operating range

Value


Digital codeSignal type / voltage

–Resistance

–Frequency



Measuring options


Yes (except Mondeo)WDS/IDS DTC

– – *Guided diagnostics (WDS/

IDS)

–DMM

– –Datalogger



required)

– –Powerprobe



* In the case of a faulty signal from the rain sensor, the windshield

wiper will constantly wipe in interval mode when the rain sensing

function is switched on.

The rain sensor can not be diagnosed.

Special features

If the rain sensor fails, the windshield wipers can still

be operated manually.

If a fault is detected while the wipers are in operation

then the wipers are left running at the last selected speed.

On some vehicles, automatic calibration takes place:

– On older versions, initialization takes place when

the rain sensing wiper function is switched on, during

which the wipers are actuated once. During this

initialization, the current condition of the windshield

is checked and any permanent blemishes within the

detection range of the sensor (for instance, due to

stone chip damage) are identified and taken into

account.

– On newer versions, automatic calibration only takes

place if the wiper switch was not set to the rain

sensing function before the ignition was switched

on.

Depending on the vehicle and the equipment, it is

possible to adjust the sensitivity of the rain sensor.

Further instructions on this can be found in the Owner's

Handbook.

In vehicles with a "Solar Reflect" infrared-reflecting

windscreen, a light/rain sensor unit is installed which

takes the coating of the windscreen into account.

This light/rain sensor unit must not be exchanged for a

unit intended for vehicles without an infrared-reflecting

windscreen, because correct operation of the rain sensor

cannot otherwise be guaranteed.



Manifold absolute pressure sensor(MAP)

E58182

3

21

Examples of MAP sensors

MAP sensor1

MAPT sensor2

IAT sensor element3

Location

In the intake system


Membrane sensors with strain resistors or piezo

Task / function

The MAP sensor measures the current intake manifold

absolute pressure.


alter depending on the manifold absolute pressure.

Operating range

Value


Direct voltage: 0-4.8 VSignal type / voltage

–Resistance

pressure-sensitive *Frequency

* Only in vehicles with EEC IV and, in some cases, EEC V systems.

To test the MAP sensor, proceed as follows: connect a

hand pump to the MAP sensor. If necessary, remove

the MAP sensor, but leave the wiring harness connector

connected; switch on the ignition.

Note: The values specified in the table may differ,

depending on the barometric air pressure (generally

between approx. 920 to 1,028 mbar).

Values for 2.0L Duratec-HE in the Mondeo 2001

Voltage (V)Absolute pressure (bar)

Approx. 4.11 (barometric pressure)

Approx. 3.30.8

Approx. 2.50.6

Approx. 1.70.4

Approx. 1.00.2

Values for 1.6L Duratorq-TDCi (DV) diesel and 2.0L

Duratorq-TDCi (DW) diesel engines


–0

Approx. 0.860.1

Approx. 10.2

Approx. 1.190.3

Approx. 1.360.4

Approx. 1.50.5




Approx. 1.680.6

Approx. 1.80.7

Approx. 20.8

Approx. 2.160.9

Approx. 2.41 (barometric pressure)

Approx. 2.521.1

Approx. 2.711.2

Approx. 2.871.3

Approx. 31.4

Approx. 3.181.5

Approx. 3.351.6

Approx. 3.521.7

Approx. 3.651.8

Approx. 3.831.9

Approx. 42

Approx. 4.22.1

Approx. 4.272.2

Approx. 4.422.3

Approx. 4.62.4

Approx. 4.72.5

In vehicles with EEC IV and, in some cases, EEC V

systems, the pressure measured by the MAP sensor is

output as a frequency value (Hz).

Values in MAP sensors with output frequency

Frequency (Hz)Pressure (bar)

155.5Barometric pressure

(measured at 980 mbar)

134.5 – 142.5800

118.4 – 126.4600

103.4 – 111.4400

89.2 – 97.2200

Note: Cracks in the sensor housing or internal damage

can lead to the correct frequency being displayed, while

the amplitude of the frequency is not actually reached.

The amplitude can be checked using the oscilloscope

(setpoint value approx. 5 V).

Measuring options


YesWDS/IDS DTC


IDS)

++DMM

++Datalogger



required)

– –Powerprobe



Note: In some vehicle versions, the actual manifold

pressure is displayed in bar instead of (or as well as) the

voltage display by the WDS/IDS datalogger.



In this case, it is possible to carry out a simple test of

the MAP sensor using the hand pump.

– Connect the hand pump to the measuring point of

the MAP sensor (if necessary, remove the MAP

sensor for this purpose).

– Depending on the combustion type (petrol or diesel),

apply a negative (petrol) or positive pressure (diesel)

in several stages to the MAP sensor.

– The values on the dial indicator gauge of the hand

pump must coincide with the displayed values in the

WDS/IDS datalogger.

Note:MAPT sensors are often used in place of MAP

sensors. In this case, an IAT sensor is integrated into

the MAP sensor.



Convertible top sensors (Focus CoupeConvertible)

Example: front striker sensors

1

2

1

2

E87733

Front right-hand striker sensor1

Front left-hand striker sensor2

Location

1 2 3 4

10 95678

1 2 3 4

10 95678

E87732



Convertible top front striker sensor RH1

Convertible top front latch operating mechanism

closed position sensor

2

Convertible top rear striker sensor3

Luggage compartment lid operating mechanism

latch sensor RH

4

Luggage compartment lid lift cylinder open

position sensor

5

Luggage compartment lid operating mechanism

latch sensor LH

6

Convertible top lift cylinder open position sensor7

Convertible top lift cylinder closed position

sensor

8

Convertible top front latch operating mechanism

open position sensor

9

Convertible top front striker sensor LH10


Hall

Task / function

Detection of the start and end positions of the

convertible top. The convertible top control module

receives a different voltage signal depending on the

sensor status ("activated" or "not activated").

Depending on the position of the convertible top, this

means that some sensors are activated and some are not

activated.

Operating range

Value


Square-wave signal: 0 or

5 V


–Resistance

–Frequency

Measuring options


YesWDS/IDS DTC


IDS)

+DMM

++Datalogger



required)

– –Powerprobe





Datalogger signals from all ten sensors OK with

convertible top "closed".

E87436

Not activatedA

ActivatedB

Defective sensorC

Datalogger signals from all ten sensors OK with

convertible top "open".

E87437

Not activatedA

ActivatedB

Defective sensorC

Datalogger signals from all ten sensors, with "defective"

sensor no. 8

E87438

Not activatedA

ActivatedB

Defective sensorC



Select-Shift switch

E58062

1

2

3

Shown: CFT23 automatic transaxle

Illumination LEDs1

Hall sensors2

Connector3

Location

On the gearshift lever (automatic transmission with

manual gear selection)


Hall

Task

The Select-Shift switch detects the manual shift mode

of the driver (Select-Shift mode).

Within the manual shift mode, the Select-Shift switch

detects whether the selector lever is actuated forwards

or backwards and generates a digital signal.

Operating range

Value


Square-wave signalSignal type / voltage

–Resistance

–Frequency

Tiptronic lead 2Tiptronic lead 1Signal Name

< 3.6 V< 1.4 V0

> 3.6 V> 3.6 V1

Tiptronic lead 2Tiptronic lead 1Function

11Automatic

mode

00Manual mode

01Tip +

10Tip -

Measuring options




IDS)

+DMM

++Datalogger



required)

– –Powerprobe





Select-Shift switches can be tested in the context of the

TR sensor test in the datalogger.

TR sensor in the datalogger

E59969

Example: Galaxy with AG5

Display of the individual transmission rangesP - 1

Display for manual gear selection (Select-Shift

switch)

MAN

The display of the gears for manual gear selection may,

depending on the vehicle equipment, also be shown in

the instrument cluster.



Passenger weight sensor

TIE45298

2

1

Sensor mat1

Sensors2

Location

Integrated in the passenger seat


Ohmic resistance

Task / function

The occupant classification sensor detects whether a

person is sitting on the passenger seat or not.

The system consists of a sensor mat which is

incorporated into the seat and consists of a large number

of small sensor cells. These sensors possess their own

module under the seat surface of the passenger seat.

This module prepares the individual signals and

transmits this information to the SRS module.

Operating range

Value


digital ON/OFFSignal type / voltage

–Resistance

–Frequency

Measuring options


Yes *WDS/IDS DTC


IDS)

– –DMM

– –Datalogger



required)

– –Powerprobe






and test routine.



The seat load sensor is continuously monitored by the

SRS module and can not be tested in the workshop.

Special features

If the passenger seat is unoccupied or a light object is

placed on it, a "seat unoccupied" signal is transmitted

to the air bag control module and the passenger air bag

is deactivated.

If the passenger seat is unoccupied and the safety belt

is fastened, the "passenger air bag deactivated" warning

indicator lights up.

The occupant classification sensor is integrated in the

passenger seat and can only be renewed together with

the seat foam element. Instructions for this can be found

in the relevant Service literature.



Occupancy sensor

E58072

1 2

shown: model with separate module

Occupancy sensor1

Control module2

Location

Integrated in the passenger seat


Ohmic resistance

Task / function

The occupancy sensor consists of a sensor loop

integrated into the seat foam and, depending on the

model, a separate occupancy detection module, which

evaluates the signals from the sensor and transmits them

to the SRS module.

The occupancy detection module is located outside the

seat.

The occupancy sensor whether a person is sitting on the

passenger seat. If a defined pressure on the sensor is

exceeded, a digital signal is generated.

Operating range

Value



–Resistance

–Frequency

Measuring options


Yes *WDS/IDS DTC


IDS)

– –DMM

– –Datalogger



required)

– –Powerprobe



* Depending on the system, the WDS indicates diagnostic trouble

codes together with the corresponding error values. Error values

are needed for error description in the FordEtis diagnostic and test

routine.

The occupancy sensor is continuously monitored by the

SRS module and can not be tested in the workshop.

Special features

The occupancy sensor is used in vehicles which possess

a seat belt warning lamp for the passenger. The

passenger air bag is not deactivated.



The occupancy sensor is integrated in the passenger seat

and can only be replaced together with the seat foam

element. Instructions for this can be found in the relevant

Service literature.



Seat position sensor

E58073

12

U-shaped Hall sensor1

Metal bar2

Location

Underneath the driver seat on the inner seat track


Hall

Task / function

The seat position sensor measures the position of the

driver seat in the longitudinal direction. If the seat is in

a forward position, a metal bar moves into the sensor.

This influences the magnetic field of the sensor and a

square-wave signal is generated.

The Hall sensor is a sensor with two connections.

Principles of Operation

E60112

1

4

3

BA

2

Control moduleA

Hall sensorB

Transistor1

Hall plate2

Metal bar3

Connector (2-pin)4

Operating range

Value


square-wave ON/OFFSignal type / voltage

–Resistance

–Frequency



Measuring options


Yes *WDS/IDS DTC


IDS)

–DMM

++Datalogger



required)

– –Powerprobe






and test routine.

The seat position sensor is continuously monitored by

the SRS module and can not be tested in the workshop.

All the possible errors in the SRS system are displayed

using fault codes.



Sun load sensor

E58064

Location

In the front area of the instrument panel (in vehicles

with EATC (Electronic Automatic Temperature Control)

and SATC (Semi-automatic Temperature Control)).


Photovoltaic effect

Task / function

The sun load sensor measures the sun intensity.

The stronger the sun intensity on the sensor, the lower

the resistance.

Operating range

Value



light: 0-1 kOhm

dark: > 4.5 MegaOhm

Resistance

–Frequency

Measuring options


YesWDS/IDS DTC


IDS)

+DMM

++Datalogger



required)

– –Powerprobe




in the datalogger.

Sun load sensor, Mondeo 2001 (06/2003-) in the datalogger

E58750

1 2

Display with sun load1

Display without sun load2

When checking the sun load sensor in the datalogger,

please note that the display in the WDS/IDS can show

a lower value than expected, even in direct sunshine.

Lighting with, for instance, a strong headlamp (not a

neon lamp) may, in some circumstances, may achieve

higher results than sunlight.



If the sensor is covered, the display must rise to the

respective maximum value (dark).

The display may have a numerical format (example:

Focus/Mondeo) or a percentage format (example:

Galaxy).



Position sensors (distance sensors)

E59109

1 2

Examples of position sensors

EGR valve position sensor (vacuum-controlled)1

EGR valve position sensor (electrically

controlled)

2

Location

The position sensors are generally integrated into the

actuator itself and are coupled directly to it.


Sliding-contact potentiometer or inductive

Task / function

Position sensors are primarily used in actuators where

a direct detection of the position of the actuator is

necessary, as for instance:

– in the vacuum-controlled EGR valve,

– in the electrically controlled EGR valve,

– position of the electronic throttle plate,

– position of the turbocharger guide vanes (variable

turbocharger in vehicles with exhaust standard level

IV),

– position of the clutch (vehicles with automated

manual transmission).

The position sensors send a feedback about the current

position of the actuator to the relevant control module.

It is therefore a closed-loop control circuit.

Measuring options

The testing possibilities for the individual position

sensors depend on the physical operating principle and

their use in the system.

For this reason, these sensors are described in the section

relating to each of the relevant actuators in the Student

Information "Actuators, CG8234/S".



Intake manifold flap position sensor(diesel engines)

E85075

Intake manifold flap position sensor

(sliding-contact potentiometer)

A

Intake manifold flap position sensor (inductive)B

Location

In the intake tract at the intake manifold flap


Sliding contact potentiometer (for example on the

2.0L Duratorq-TDCi (Puma) diesel engine with diesel

particulate filter in the 2001 Mondeo)

Inductive sensor (for example on the 2.0L

Duratorq-TDCi (DW) diesel engine with diesel

particulate filter in the 2006.5 S-Max/Galaxy)

Task / function

NOTE: In contrast to most petrol engines, the intake

manifold flap is only used under certain operating

conditions in diesel engines.

Sliding-contact potentiometer:

– When the throttle plate is closed, a sliding contact

moves onto a resistance track in the position sensor.

– During closing of the intake manifold flap, the

resistance of the sensor drops proportionally with

the intake manifold flap position.

Inductive senor:

– When the intake manifold flap is closed, a rotor

moves which induces an alternating voltage from

the primary coil to the secondary coil.

– The strength of the induction depends on the position

of the rotor.

– In the integrated sensor circuit, the induced

alternating current is converted into direct current

(= output voltage).

– During closing of intake manifold flap, the output

voltage of the sensor falls proportionally with the

intake manifold flap position.

Operating range

Value



- (inductive)Resistance

–Frequency



Sensor values on the 2.0L Duratorq-TDCi (Puma)

diesel engine with diesel particulate filter in the 2001

Mondeo

Voltage (V)Pressure (mbar)Throttle position

Approx. 3.90 (barometric

pressure)

fully open

Approx. 3.5–100–

Approx. 2.5–200–

Approx. 1.2–300–

Approx. 0.3–400fully closed

Sensor values on the 2.0L Duratorq-TDCi (DW)

diesel engine with diesel particulate filter in the 2001

Mondeo

Voltage (V)Pressure (mbar)Throttle Position

Approx. 4.30 (barometric

pressure)

fully open

Approx. 3.7–200–

Approx. 2.3–400–

Approx. 1Approx. –600fully closed

Measuring options


YesWDS/IDS DTC


IDS)

++DMM

++Datalogger



required)

– –Powerprobe




The intake manifold flap position sensor can be checked

using the vacuum hand pump and the WDS/IDS

datalogger. To perform the check, connect the vacuum

hand pump to the vacuum unit of the intake manifold

flap.

Intake manifold flap position sensor signal of the 2006.50

Galaxy with 2.0L Duratorq-TDCi (DW) diesel when the

engine is switched off

1 1

2

E87773

The intake manifold flap is fully open1

The intake manifold flap is fully closed2

Continuity test

With the aid of the oscilloscope, a continuity test can

be carried out on the signal wire of the intake manifold

flap position sensor.

Move the intake manifold flap progressively from the

"fully closed" to the "fully open" position using the

vacuum hand pump for this purpose. The voltage change

must also be displayed continuously on the oscilloscope.

In the case of erratic voltage changes or voltage peaks

outside the specified voltage range, the intake manifold

flap position sensor is faulty.



Note on sliding-contact potentiometers:

– Hairline cracks or similar in the sensor may lead to

faults at low temperatures which might no longer




Ultrasonic sensor for parking aid

TIE41677

Location

In the front and rear bumper

Task / function

Ultrasonic sensors for parking aid systems measure the

distance between the installation location of the sensor

and an obstacle.

The sensor outputs a digital signal in the form of a

frequency depending on the distance it has measured.

The smaller the distance, the higher the frequency.

Operating range

Value

Approx. 8 V/12 VSupply voltage

digitalSignal type / voltage

–Resistance

46.5 kHz-50 kHzFrequency

30 cm-max. 150 cmMeasurement range

Measuring options


Yes *

No (all others)

WDS/IDS DTC

+ (self-test)Guided diagnostics (WDS/

IDS)

–DMM

++ *

- - (all others)

Datalogger



required)

– –Powerprobe



* Focus C-MAX 2003.75 (06/2003-), Focus 2004.75 (07/2004-),

Galaxy 2000.75 (04/2000-), Transit 2000.5 (01/2000-)


in the datalogger.

Signal trace with constant tone (rear parking aid sensors,

Focus 2004.75) in the datalogger

E59082

The shape of the bumper leads to the different distances

between the outer and inner sensors.



The values correspond to the distance to the obstacle

including a defined offset, which is taken into account

in the calculation for safety reasons.

Systems in which a separately fitted module for

controlling the parking aid is installed can be tested

using an integrated self-test.

In some systems, the parking aid must be activated for

this purpose (Valeo) or a coding connector must be

disconnected before switching on (Bosch). The precise

procedure for activating the test can be found in the

current Service literature.

The proper function can also be tested by touching the

activated sensor lightly. It should be possible to feel a

vibration on the sensor surface.

Moreover, please check that the sensors are in perfect

condition and are free of soiling. The paint coating on

the ultrasonic sensors must also have a precisely defined

thickness.

In heavy rain and/or physically unfavourable reflection

conditions, reliable detection of the nearest obstacle is

not always guaranteed, since the ultrasonic waves may

be subject to unwanted reflection.




1. Which test devices are recommended for testing temperature sensors?

a. The oscilloscope only

b. The DMM only

c. The WDS/IDS datalogger and the DMM

d. The Ford temperature sensor tester or the oscilloscope

2. Which type of signal is output by a Hall sensor?

a. Square-wave signal

b. Sinusoidal signal

c. Linear direct-voltage signal

d. A square-wave signal or a sinusoidal signal, depending on the type

3. What can be determined by the continuity test on sliding-contact potentiometers?

a. The voltage supply of the sensor is in order.

b. There is a continual short circuit in the wiring harness.

c. There is a continuous open circuit in the wiring harness.

d. Cracks or soiling influence the resistance track of the sensor.

4. In inductive speed sensors, what changes when the speed changes?

a. The signal frequency only

b. The height of the signal amplitude only

c. The duty cycle of the PWM signal

d. The height of the signal amplitude and the signal frequency

5. Which test is recommended for inductive sensors (among other areas)?

a. Resistance test

b. Continuity test

c. Pressure test

d. Powerprobe


Lesson 2 – SensorsTest questions

6. Hall sensors do not require any reference voltage or voltage supply.

a. true

b. false

7. What should be noted when doing measuring work with the oscilloscope?

a. For this measurement, the vehicle battery must be disconnected without fail.

b. For this measurement, terminal probes must be produced which can be inserted into the wiring-harness

connector on the sensor.

c. The relevant wiring-harness connector must be disconnected from the sensor for measurements with the

oscilloscope.

d. The measurement must be carried out with a breakout box or an appropriate adapter cable.

8. Which tool is recommended for the graphic representation of sensor signals?

a. DMM

b. WDS/IDS datalogger

c. Signal configurator

d. WDS/IDS signal generator


Test questionsLesson 2 – Sensors

Brake pressure switch

E30134

1

2

Brake pressure switch1

Plug connection2

Location

In the brake line (Mondeo with 5F31J /Galaxy with

AG5; in both cases only with a diesel engine and without

stability assist).


Pressure switch (normally open contact)

Task / function

The brake pressure switch registers braking pressure in

the brake system's hydraulic circuit. This switch closes

when a defined pressure is reached.

Operating range

Value

Approx. 12 VVoltage


Open > 50 kOhm

Closed < 0.5 Ohm

Resistance

Testing options


NoWDS/IDSDTC


IDS)

++DMM

+ (Galaxy)

- (Mondeo)

Datalogger



required)

–Powerprobe




Lesson 3 – SwitchesPressure switch

Refrigerant pressure switch

E59764

3

21

Examples of refrigerant pressure switches

Refrigerant low-pressure switch1

Dual pressure switch2

Refrigerant high-pressure switch3

Location

On the high and low pressure sides of the A/C


Pressure switch (normally closed/normally open contact)

Task / function

Also refer to the refrigerant pressure sensor.

A refrigerant pressure switch registers pressure on the

air-conditioning system's high and low pressure sides.

This switch opens on attainment of a defined pressure.

High-pressure switches are often designed as dual

components (4 terminals) operating in two stages:

– Stage 1 for fan control (closes)

– Stage 2 for compressor (opens)

Air conditioning systems with a thermostatic expansion

valve are equipped with a 3-stage pressure switch on

the high-pressure side.

– Stage 1 for minimum pressure

– Stage 2 for fan control

– Stage 3 for maximum pressure

Operating range

Value

Approx. 5 V / 12 VVoltage


Open > 50 kOhm

Closed < 0.5 Ohm

Resistance

Refrigerant high / dual pressure switch

FunctionPressure (bar)

Compressor ON< approx. 29

Compressor OFF> approx. 33.5

Fan stage 2 / high-speed fan *approx. 25

* Only dual pressure switch

Refrigerant low-pressure switch


Compressor ON> approx. 3.2

Compressor OFF< approx. 1.5

Refrigerant 3-stage switch pressure switch


Minimum stage opens< approx. 1.5

Maximum stage closesApprox. 16

Maximum stage opensApprox. 32

Fan stage 2 / high-speed fanApprox. 24



Testing options


RestrictedWDS/IDS DTC


IDS)

++DMM

–Datalogger



required)

–Powerprobe



Refrigerant pressure switches should always be tested

in the installed state.

Special features

Refrigerant pressure switches also have the following

designations:

– High-pressure limit switch

– Low-pressure limit switch

– Refrigerant high-pressure switch

– Refrigerant low-pressure switch

– Cycle switch

– Compressor clutch switch

– Pressure limit switch



Oil pressure switch.

E59866

Examples of oil pressure switches

Location

On the engine block


Pressure switch (normally closed contact)

Task / function

An oil pressure switch registers engine oil pressure. This

switch opens when a defined pressure is reached.

Oil pressure switches only have one connection cable.

Earthing is via the housing.

Operating range

Value

Approx. 12 VVoltage


Open > 50 kOhm

Closed < 0.5 Ohm

Resistance

Testing options


No (warning lamp)WDS/IDS DTC


IDS)

++DMM

+ (restricted)Datalogger



required)

–Powerprobe





PSP (Power Steering Pressure) switch

E58061

Location

On the power steering pump or in the power steering

line, depending on the vehicle.


Switch (normally closed contact)

Task / function

The PSP registers pressure in the line between the power

steering pump and steering gear. This switch opens on

attainment of a defined pressure.

Operating range

Value

Approx. 12 VVoltage


Open > 50 kOhm

Closed < 0.5 Ohm

Resistance

Testing options


NoWDS/IDS DTC


IDS)

++DMM

++Datalogger



required)

–Powerprobe



Special features

Vehicles equipped with a diesel engine do not require

a PSP switch due to the high torque output of the engine.



Brake light switch / brake pedal position(BPP) switch / clutch pedal position(CPP) switch

E58056

1 2

CPP (Clutch Pedal Position) switch1

BPP (Brake Pedal Position) switch / brake light

switch

2

Location

- On the brake pedal (BPP switch / stoplamp switch)

- On the clutch pedal (CPP switch)


- BPP switch; (normally closed contact)

– CPP switch; (normally closed/normally open contact)

– Stoplamp switch; (normally open contact)

Task / function

CPP switch, BPP switch and stoplamp switch detect the

positions of the clutch and brake pedals.

On actuation of the brake pedal:

– the BPP switch opens

– the stoplamp switch closes

Depending on the vehicle / engine, the switching points

of the brake light and BPP switch are either identical or

mutually offset.

On actuation of the clutch pedal:

– the CPP switch opens

The CPP can be designed as a single stage or two stage

switch with different switching points, i.e. stage 1 opens,

stage 2 closes (example: 115 PS Mondeo 2001 with

speed control system).

Operating range

Value

Approx. 5 V / 12 V for CPP

switch

Approx. 5 V for BPP switch

Approx. 12 V for brake light

switch

Voltage


Open > 50 kOhm

Closed < 0.5 Ohm

Resistance

Testing options


Yes *WDS/IDS DTC

++ *Guided diagnostics (WDS/

IDS)

++DMM

++ *Datalogger



required)

–Powerprobe



Mechanical switchLesson 3 – Switches



* Not for the stoplamp switch

Special features

The brake light switch is also termed BOO (brake ON

/ OFF switch).


Lesson 3 – SwitchesMechanical switch

Defrosting switch.

E59111

1

3

2

Connector1

Relay.2

Temperature sensor3

Location

On the evaporator


A switch (relay) in conjunction with a NTC sensor

(normally closed contact).

Task / function

The temperature sensor on the defrosting switch

measures the temperature of the evaporator. The relay

opens when the temperature drops below a defined limit.

Operating range

Value



Open > 50 kOhm

Closed < 0.5 Ohm

Resistance

Switching point (degrees

Celsius)

Vehicle

2Galaxy

4Escort/Scorpio

Testing options


NoWDS/IDS DTC


IDS)

++DMM

– –Datalogger



required)

–Powerprobe





Seatbelt buckle switch

E58066

2

3

1

Belt buckle with an integrated switch1

Pyrotechnic seatbelt pretensioner2

Wire for buckle switch3

Location

Integrated into the seatbelt buckle


Switch (normally closed contact), except for Mondeo

2001 (Hall)

Task / function

The seatbelt buckle switch identifies the setting of the

buckle's catch. This switch opens when the catch

engages.

Operating range

Value

Approx. 5 V (switch)

Millivolts (Hall)

Voltage

Supply voltage

ON / OFF (switch)

Digital (Hall)


Open > 50 kOhm *

Closed < 0.5 Ohm *

Resistance

* Not measurable in the case of Hall

Testing options


No (switch)

Yes (Hall) *

WDS/IDS DTC


IDS)

+ (switch)

- (Hall)

DMM

+ (Hall)

- (switch)

Datalogger



required)

–Powerprobe






and test routine.



Special features

For the European market, the Mondeo 2001 was

equipped with Hall sensors as safety belt buckle

switches from 2001 to 2002. These cannot be

distinguished from the regular switches from the outside.

If a Hall sensor malfunctions, a DTC is stored in the

SRS module.



Rear door window switch strip

Note: Is only installed on the 2006.50 Galaxy.

11

E88597

Window switch strip1

Location

In the window frames of the rear doors


Normally open contact

Task / function

On the 2006.50 Galaxy, the rear door window switch

strip is installed as an additional pinch protection for

the power windows.

The switch strip consists of two conducting materials,

which are separated from each other along its entire

length.

If pressure is exerted at a point in the switch strip, the

conductor materials contact one another and short

circuit.

Operating range

Value


Analog DC voltage

Not operated: 2.8 – 4.1 V

Operated: 0 – 2.8 V

Open circuit: 4.1 – 5 V


Not operated, approx. 3.9

kOhm

Operated: < 2.0 kOhm

Open circuit = infinite

Resistance

* Not measurable in the case of Hall

Testing options


YesWDS/IDS DTC


IDS)

++DMM

– –Datalogger



required)

– –Powerprobe





Inertia fuel shutoff (IFS) switch

E58060

1

23

4

Reset button for closing the current circuit (after

triggering)

1

Ball seat with magnet2

Ball3

Switches4

Location

– At the A-pillar (on vehicles with petrol or diesel

engine in conjunction with a VP44 distributor-type

injection pump and all Galaxy models)

– In the luggage compartment (on older vehicles)


Ball-and-socket switch (normally closed contact)

Task / function

The IFS (Inertia Fuel Shutoff) interrupts the power

supply to the fuel pump in case of a shock (retardation

on impact).

This electric ON / OFF switch operates on the principle

of inertia.

On an occurrence of rapid retardation (impact speed in

excess of 20 km/h), a ball overcomes a magnetic force

previously retaining the ball in its socket. This presses

the switch up and interrupts the power circuit.

To close the power circuit (after triggering), the switch

must be pressed down again manually by means of the

reset button.

Operating range

Value

Approx. 12 VVoltage


Open > 50 kOhm

Closed < 0.5 Ohm

Resistance

Testing options


Yes *WDS/IDS DTC


IDS)

+DMM

– –Datalogger



required)

–Powerprobe



* Error indicates interruption in the fuel pump secondary circuit



Brake fluid switch

E59848

1

2

1A B

Examples of brake fluid switches

Switch integrated into the brake fluid reservoirA

Switch integrated into the brake fluid reservoir

lid

B


Float2

Location

On the brake fluid reservoir.


Switch or reed contact (normally open)

Task / function

A brake fluid switch registers the brake fluid level. If

the brake fluid drops below a defined level, the switch

closes.

Operating range

Value

Approx. 12 VVoltage


Open > 50 kOhm

Closed < 0.5 Ohm

Resistance

Testing options




IDS)

++DMM

–Datalogger



required)

–Powerprobe



Special features

A switch integrated into the brake fluid reservoir cannot

be replaced separately.



Switch for windshield washer / coolantlevel

E59798

1

2

Example of a windshield washer switch

Housing with reed contact (glass tube)1

Float with an integrated magnet2

Location

On the windshield washer reservoir or coolant expansion

tank (vehicles with an additional warning system or

driver information system)


Reed contact (normally closed or open)

Task / function

This switch registers the level of the windshield washer

fluid or coolant. If the windshield washer fluid or

coolant drops below a defined level, the switch opens

or closes.

Operating range

Value

Approx. 5 VVoltage


Open > 50 kOhm

Closed < 0.5 Ohm

Resistance

Testing options




IDS)

++DMM

–Datalogger



required)

–Powerprobe





Reversing lamp switch

E59847

Examples of reversing light switches

Location

On the transmission housing (gearbox)


Mechanical switch (normally open contact)

Task / function

The reversing light switch registers the gearshift shaft's

position. This switch closes when reverse gear is

engaged.

Operating range

Value

Approx. 12 VVoltage


Open > 50 kOhm

Closed < 0.5 Ohm

Resistance

Testing options


NoWDS/IDS DTC


IDS)

++DMM

+ (restricted)*Datalogger



required)

–Powerprobe



* On vehicles requiring the reversing lamp switch signal for engine

control functions such as torque limitation.

If a reversing light switch malfunctions, the light no

longer comes on when reverse gear is engaged.



Audio remote control

E59872

1

Examples of audio remote controls

Variant with a button for speech control1

Location

On the steering column


Voltage-coded switch

Task / function

Pressing a button generates a voltage signal whose value

depends on the resistance integrated into the switch.

Operating range

Value

Approx. 5 VVoltage

Direct voltageSignal type / voltage

see tableResistance

ResistanceSwitches

Approx. 5 kOhmNo buttons pressed

Approx. 0.3 kOhmSEEK up

Approx. 0.5 kOhmSEEK down

Approx. 1 kOhmMODE

Approx. 150 OhmVOL Up

Approx. 50 OhmVOL -

Approx. 2 kOhmVOICE

Testing options


NoWDS/IDS DTC


IDS)

++DMM

+ (restricted)*Datalogger



required)

–Powerprobe



* On the Mondeo from MY 2003.75, Focus C-MAX 2003.75 and

Focus 2004.75

The audio remote control can only be replaced as a

complete unit.



Speed control switch

E59867

Mondeo 2001 is shown

Location

On the steering wheel


Voltage-coded switch

Task / function

Pressing a button generates a voltage signal whose value

depends on the resistor integrated into the switch.

Operating range

Value

Approx. 5 VVoltage

Direct voltageSignal type / voltage

see tableResistance

Not applicable to the Galaxy

Resistance (ohm)Switches

Approx. 2100No buttons pressed

Approx. 830 - 1100ON

Approx. 1 - 4OFF

Approx. 2250 - 2200Readjustment (=)

Approx. 110 - 130Retardation (-)

Approx. 300 - 400SET- / acceleration (+)

Testing options


NoWDS/IDS DTC


IDS)

++DMM

– –Datalogger



required)

–Powerprobe



The speed control switches cannot be replaced

separately.



Other switches

The switches below are mechanical switches designed

to interrupt / restore ground connections.

The switch designation indicates its function and

installation position:

– Window control switch

– Tailgate release switch

– Luggage compartment lid release switch

– Luggage compartment lid contact switch

– Loading door contact switch

– Hood contact switch

– Overdrive switch (on the selector lever of vehicles

with automatic transmission)

– Parking brake indicator switch

– PNP (Park/Neutral Position) switch (in selector lever

in vehicles with automatic transmission)

– Select-shift switch on the steering wheel (in vehicles

with automatic transmission and manual gear

selection)

– Lock cylinder position switch

– Door contact switch (integrated into the door lock

on new vehicles)

– Door lock switch (integrated into the door lock on

new vehicles)

Window control switch

Window lift switches operate in one or two stages (for

each direction) depending on the design. The second

stage is needed for the window regulator one-touch

up/down function.

Depending on the design, the switch features integrated

electronics (e.g., Focus with front window regulators

from 08/2000).

Switch diagnosis differs accordingly. Additional details

are provided in the latest circuit diagrams.




1. Where are refrigerant pressure switches located?

a. Only on the high-pressure side of the refrigerant circuit.

b. Only on the low-pressure side of the refrigerant circuit.

c. On the high- or low-pressure side of the refrigerant circuit, depending upon the function.

d. Always in the dryer.

2. Which principle do liquid level switches normally operate on?

a. Inductive

b. Hall

c. Reed contact

d. Sliding contact potentiometer

3. Which of the following statements is true?

a. All switches have normally closed contacts.

b. All switches have normally open contacts.

c. Switches can feature either normally closed or open contacts.

d. All the switches are mechanical.

4. Switches can always be represented with the aid of the WDS/IDS in the data logger.

a. True

b. False

5. On which principle do radio remote control and speed control switches operate?

a. Hall

b. Inductive

c. Sliding contact potentiometer

d. Voltage coding


Lesson 3 – SwitchesTest questions

6. Low-pressure switches often operate in two stages.

a. True

b. False


Test questionsLesson 3 – Switches


1. d

2. b

3. b

4. d

5. b

6. a

7. c


1. c

2. a

3. d

4. d

5. a

6. b

7. d

8. b


1. c

2. c

3. c

4. b

5. d

6. b

Service Training166

Answers to the test questions

Air ConditioningA/C

Anti-lock Brake SystemABS

Accelerator Pedal PositionAPP

Barometric PressureBARO

Brake Pedal PositionBPP

Cylinder Head TemperatureCHT

Crankshaft PositionCKP

Camshaft PositionCMP

Clutch Pedal PositionCPP

Diagnostic Trouble CodeDTC

Electronic Automatic Temperature ControlEATC

Electronic Crash SensorECS

Engine Coolant TemperatureECT

Exhaust Gas RecirculationEGR

Fuel Pump Driver ModuleFPDM

Generic Electronic ModuleGEM

Hydraulic Control UnitHCU

Heated Oxygen SensorHO2S

Intake Air TemperatureIAT

Integrated Diagnostic SystemIDS

Inertia Fuel ShutoffIFS

Knock SensorKS

Mass Air FlowMAF

Manifold Absolute PressureMAP

Manifold Absolute Pressure And

Temperature

MAPT

Negative Temperature CoefficientNTC

Output Shaft SpeedOSS

Powertrain Control ModulePCM

Park/neutral PositionPNP

Power Steering PressurePSP

Positive Temperature CoefficientPTC

Pulse Width ModulationPWM

Semi-automatic Temperature ControlSATC

Supplemental Restraint SystemSRS

Transmission Control ModuleTCM

Transmission Fluid TemperatureTFT

Throttle PositionTP

Transmission RangeTR

Turbine Shaft SpeedTSS

Vehicle Speed SensorVSS

Worldwide Diagnostic SystemWDS

Wide Open ThrottleWOT

167Service Training

List of Abbreviations

curriculum training

Documents

control of actuators

ford training purposes

training literature

connected sensors

installed sensors

control technology

s tc4012041h actuators

measurement variables