wheel FORD SIERRA 1990 2.G Engine Electrical Systems Workshop Manual

General information
The electrical system is of the 12 volt
negative earth type, and consists of a 12 volt
battery, alternator with integral voltage
regulator, starter motor and related electrical
accessories, components and wiring. The
battery is of the low maintenance or
maintenance-free “sealed for life” type and is
charged by an alternator which is belt-driven
from the crankshaft pulley. The starter motor
is of the pre-engaged type, incorporating an
integral solenoid. On starting the solenoid
moves the drive pinion into engagement with
the flywheel ring gear before the starter motor
is energised. Once the engine has started, a
one-way clutch prevents the motor armature
being driven by the engine until the pinion
disengages from the flywheel.
The ignition system is responsible for
igniting the air/fuel mixture in each cylinder at
the correct moment in relation to engine
speed and load. A number of different ignition
systems are fitted to models within the
Sierra/P100 range, ranging from a basic
breakerless electronic system to a fully
integrated engine management system
controlling ignition and fuel injection systems.
The ignition system is based on feeding low
tension voltage from the battery to the coil
where it is converted to high tension voltage.
The high tension voltage is powerful enough
to jump the spark plug gap in the cylinders
many times a second under high compression
pressures, providing that the system is in
good condition. The low tension (or primary)
circuit consists of the battery, the lead to the
ignition switch, the lead from the ignition
switch to the low tension coil windings
(terminal + /15) and also to the supply terminal
on the electronic module, and the lead from
the low tension coil windings (terminal -/1) to
the control terminal on the electronic module.
The high tension (or secondary) circuit
consists of the high tension coil windings, the
HT (high tension) lead from the coil to the
distributor cap, the rotor arm, the HT leads to
the spark plugs, and the spark plugs.
The system functions in the following
manner. Current flowing through the low
tension coil windings produces a magnetic
field around the high tension windings. As the
engine rotates, a sensor produces an
electrical impulse which is amplified in the
electronic module and used to switch off the
low tension circuit.
The subsequent collapse of the magnetic
field over the high tension windings produces
high tension voltage which is then fed to the
relevant spark plug via the distributor cap and
rotor arm. The low tension circuit is
automatically switched on again by the
electronic module, to allow the magnetic field
to build up again before the firing of the next
spark plug. The ignition is advanced and
retarded automatically to ensure that thespark occurs at the correct instant in relation
to the engine speed and load.
To improve driveability during warm-up
conditions and to reduce exhaust emission
levels, a vacuum-operated,
temperature-sensitive spark control system is
fitted to certain vehicles.Inductive discharge system
This is the least sophisticated system fitted
to the Sierra/P100 range, and comprises a
breakerless distributor and an electronic
switching/amplifier module in addition to the
coil and spark plugs.
The electrical impulse which is required to
switch off the low tension circuit is generated
by a magnetic trigger coil in the distributor. A
trigger wheel rotates within a magnetic stator,
the magnetic field being provided by a
permanent magnet. The magnetic field across
the two poles (stator arm and trigger wheel) is
dependent on the air gap between the two
poles. When the air gap is at its minimum, the
trigger wheel arm is directly opposite the
stator arm, and this is the trigger point. As the
magnetic flux between the stator arm and
trigger wheel varies, a voltage is induced in
the trigger coil mounted below the trigger
wheel, and this voltage is sensed and then
amplified by the electronic module and used
to switch off the low tension circuit. There is
one trigger wheel arm and one stator arm for
each cylinder (4).
The ignition advance is a function of the
distributor and is controlled both mechanically
and by a vacuum operated system. The
mechanical governor mechanism consists of
two weights which move out from the
distributor shaft as the engine speed rises due
to centrifugal force. As they move outwards,
they rotate the trigger wheel relative to the
distributor shaft and so advance the spark.
The weights are held in position by two light
springs and it is the tension of the springs
which is largely responsible for correct spark
advancement.
The vacuum control consists of a
diaphragm, one side of which is connected
via a small bore hose to the carburettor or
inlet manifold and the other side to the
distributor. Depression in the inlet manifold
and/or carburettor, which varies with engine
speed and throttle position, causes the
diaphragm to move, so moving the baseplate
and advancing or retarding the spark. A fine
degree of control is achieved by a spring in
the diaphragm assembly.
ESC (Electronic Spark Control) system
This system is only fitted to early
“Economy” models, and comprises a “Hall
effect” distributor, and an ESC module, in
addition to the coil and spark plugs.
The electrical impulse which is required to
switch off the low tension circuit is generated
by a sensor in the distributor. A trigger vane
rotates in the gap between a permanent
magnet and the sensor. The trigger vane has
four cut-outs, one for each cylinder. When
one of the trigger vane cut-outs is in line with
the sensor, magnetic flux can pass betweenthe magnet and the sensor. When a trigger
vane segment is in line with the sensor, the
magnetic flux is diverted through the trigger
vane away from the sensor. The sensor
senses the change in magnetic flux and sends
an impulse to the ESC module, which
switches off the low tension circuit.
The ignition advance is a function of the
ESC module and is controlled by vacuum. The
module is connected to the inlet manifold by a
vacuum pipe, and a transducer in the module
translates the vacuum signal into electrical
voltage. From the vacuum signal, the ESC
module determines engine load, and engine
speed is determined from the interval
between impulses supplied by the distributor
sensor. The module has a range of spark
advance settings stored in its memory, and a
suitable setting is selected for the relevant
engine speed and load. The degree of
advance can thus be constantly varied to suit
the prevailing engine speed and load
conditions.
ESC II (Electronic Spark Control II)
system
1.8 and 2.0 litre SOHC carburettor models
This system is a development of the ESC
system described previously in this Section,
but it enables more accurate control of engine
operation due to the inclusion of additional
monitoring features and control outputs.
Vehicles fitted with the ESC II system have an
electric inlet manifold heater which warms the
air/fuel mixture when the engine is cold, thus
reducing the amount of fuel enrichment
required, lowering fuel consumption and
improving driveability when the engine is cold.
The heater is operated by the ESC II module
receiving information on the engine temperature
from an engine coolant temperature sensor
mounted in the inlet manifold.
On 2.0 litre SOHC models, the ESC II
module operates a carburettor stepper motor
to control the engine idle speed. Using
information on engine speed, load,
temperature and throttle position (supplied by
a switch on the carburettor), the module
operates the stepper motor to maintain a
constant idle speed. On models equipped
with automatic transmission and/or air
conditioning, additional inputs are supplied to
the module to allow it to operate the stepper
motor to compensate for the additional engine
load imposed by the automatic
transmission/air conditioning. The ESC II
module also operates a “power hold” relay
which allows the stepper motor to function
briefly after the ignition has been switched off
in order to perform an anti-run-on and
manifold ventilation cycle.
2.0 litre DOHC carburettor models
A development of the ESC II system is used
to control the operation of the engine. The
module receives information from a
crankshaft speed/position sensor (similar to
that described for the ESC Hybrid system),
except that the sensor is activated by a
toothed disc on the rear of the crankshaft,
inside the cylinder block), and an engine
coolant temperature sensor.
1General information and
precautions
Engine electrical systems 5•3
5

The ignition advance is a function of the
ESC II module, and is controlled by vacuum.
The module is connected to the carburettor
by a vacuum pipe, and a transducer in the
module translates the vacuum signal into an
electrical voltage. From the vacuum signal,
the module determines engine load; engine
speed and temperature are determined from
the crankshaft speed/position sensor and the
engine coolant temperature sensor. The
module has a range of spark advance settings
stored in its memory, and a suitable setting is
selected for the relevant engine speed, load
and temperature. The degree of advance can
thus be constantly varied to suit the prevailing
engine speed and load conditions.
ESC Hybrid (Electronic Spark Control
Hybrid) system
This system is fitted to 1.8 CVH models,
and comprises various sensors and an ESC
Hybrid module, in addition to the coil and
spark plugs. The distributor serves purely to
distribute the HT voltage to the spark plugs
and consists simply of a rotor arm mounted
directly on the end of the camshaft, and a
distributor cap.
The electrical impulse which is required to
switch off the low tension circuit is generated
by a crankshaft speed/position sensor which
is activated by a toothed wheel on the
crankshaft. The toothed wheel has 35 equally
spaced teeth with a gap in the 36th position.
The gap is used by the sensor to determine
the crankshaft position relative to TDC (top
dead centre) of No 1 piston.
Engine load information is supplied to the
ESC Hybrid module by a vacuum transducer
within the module which is connected to the
inlet manifold by a vacuum pipe. Additional
inputs are supplied by an inlet
manifold-mounted engine coolant temperature
sensor, and an air charge temperature sensor
mounted in the base of the air cleaner. The
module selects the optimum ignition advance
setting based on the information received from
the various sensors. The degree of advance
can thus be constantly varied to suit the
prevailing engine conditions.
In addition to the ignition circuit, the module
also controls an electric choke heater, and a
solenoid valve which in turn controls a throttle
damper on the carburettor. The electric choke
heater is operated by the module using
information supplied by the engine coolant
temperature sensor. The heater is used to
slow down the rate at which the choke comes
off, thereby improving driveability and overall
fuel consumption when the engine is cold. The
solenoid valve controls the vacuum supply to
the carburettor throttle damper. The throttle
damper prevents sudden closing of the throttle
during deceleration, thus maintaining
combustion of the air/fuel mixture which
reduces harmful exhaust gas emissions.
Note that there is no provision for
adjustment of ignition timing with the ESC
Hybrid system.
EEC IV (Electronic Engine Control IV)
system
2.0 litre SOHC fuel injection models
This system controls both the ignition and
fuel injection systems. The EEC IV module
receives information from a “Hall effect”
distributor sensor (similar to that described
previously in this Section for the ESC system),
an engine coolant temperature sensor
mounted in the inlet manifold, a throttle
position sensor, and an air flow meter.
Additionally, on models equipped with
automatic transmission and/or air
conditioning, additional inputs are supplied to
the module to allow it to raise the idle speed
to compensate for the additional engine load
imposed by the automatic transmission/air
conditioning. The module provides outputs to
control the fuel pump, fuel injectors, idle
speed, and ignition circuit. Using the inputs
from the various sensors, the EEC IV module
computes the optimum ignition advance, and
fuel injector pulse duration to suit the
prevailing engine conditions. This system
gives very accurate control of the engine
under all conditions, improving fuel
consumption and driveability, and reducing
exhaust gas emissions. A “limited operation
strategy” (LOS) means that the vehicle is still
driveable, albeit at reduced power and
efficiency, in the event of a failure in the
module or its sensors.
2.0 litre DOHC fuel injection models
A development of the EEC IV system is
used to control both the ignition and fuel
injection systems. The module receives
information from a crankshaft speed/position
sensor (similar to that described for the ESC
Hybrid system), except that the sensor is
activated by a toothed disc on the rear of the
crankshaft, inside the cylinder block), a
throttle position sensor, an engine coolant
temperature sensor, a fuel temperature
sensor, an air charge temperature sensor, a
manifold absolute pressure (MAP) sensor, and
a vehicle speed sensor (mounted on the
gearbox). Additionally, on models with a
catalytic converter, an additional input is
supplied to the EEC IV module from an
exhaust gas oxygen (HEGO) sensor. On
models with automatic transmission,
additional sensors are fitted to the
transmission, to inform the EEC IV module
when the transmission is in neutral, and when
the kickdown is being operated.
The module provides outputs to control the
fuel pump, fuel injectors, idle speed, ignition
system and automatic transmission.
Additionally, on models with air conditioning,
the EEC IV module disengages the air
conditioning compressor clutch when starting
the engine, and when the engine is suddenly
accelerated. On models fitted with a catalytic
converter, the EEC IV module also controls
the carbon canister-purge solenoid valve.
Using the inputs from the various sensors,
the EEC IV module computes the optimum
ignition advance, and fuel injector pulse
duration to suit the prevailing engine
conditions. A “limited operation strategy” (LOS)means that the vehicle is still driveable, albeit at
reduced power and efficiency, in the event of a
failure in the module or one of its sensors.
1.6 litre and 1.8 litre (R6A type) CVH models
A development of the EEC IV system is
used to control both the ignition and fuel
injection systems. A fully electronic
Distributorless Ignition System (DIS) is fitted,
replacing the mechanical distribution of high
tension voltage (by a rotating distributor) with
“static” solid-state electronic components.
The system selects the most appropriate
ignition advance setting for the prevailing
engine operating conditions from a three-
dimensional map of values stored in the EEC
IV control module memory. The module
selects the appropriate advance value
according to information supplied on engine
load, speed, and operating temperature from
various sensors.
The EEC IV module receives information
from a crankshaft speed/position sensor
(similar to that described for the ESC Hybrid
system), except that on 1.6 litre engines, the
sensor is activated by a toothed disc on the
flywheel), a throttle position sensor, an engine
coolant temperature sensor, an air charge
temperature sensor, a manifold absolute
pressure (MAP) sensor, a vehicle speed
sensor (mounted on the gearbox), and an
exhaust gas oxygen sensor.
The module provides outputs to control the
fuel pump, fuel injector, throttle valve control
motor, pulse-air control solenoid, carbon
canister purge solenoid (where applicable),
and the ignition system.
Using the inputs from the various sensors,
the EEC IV module computes the optimum
ignition advance and fuel injector pulse dura-
tion to suit the prevailing engine conditions. A
“limited operation strategy” (LOS) means that
the vehicle will still be driveable, albeit at
reduced power and efficiency, in the event of
a failure in the module or one of its sensors.
Precautions
General
It is necessary to take extra care when
working on the electrical system to avoid
damage to semi-conductor devices (diodes
and transistors), and to avoid the risk of
personal injury. In addition to the precautions
given in the “Safety first!” Section at the
beginning of this manual, take note of the
following points when working on the system.
Always remove rings, watches, etc before
working on the electrical system. Even with
the battery disconnected, capacitive
discharge could occur if a component live
terminal is earthed through a metal object.
This could cause a shock or nasty burn.
Do not reverse the battery connections.
Components such as the alternator or any
other having semi-conductor circuitry could
be irreparably damaged.
If the engine is being started using jump
leads and a slave battery, connect the
batteries positive to positive and negative to
negative. This also applies when connecting a
battery charger.
5•4Engine electrical systems

Never disconnect the battery terminals, or
alternator multi-plug connector, when the
engine is running.
The battery leads and alternator multi-plug
must be disconnected before carrying out any
electric welding on the car.
Never use an ohmmeter of the type
incorporating a hand cranked generator for
circuit or continuity testing.
Ignition and engine management
systems
Engine management modules are very
sensitive components, and certain
precautions must be taken to avoid damage
to the module when working on a vehicle
equipped with an engine management system
as follows.
When carrying out welding operations on
the vehicle using electric welding equipment,
the battery and alternator should be
disconnected.
Although underbonnet-mounted modules
(all except EEC IV) will tolerate normal
underbonnet conditions, they can be
adversely affected by excess heat or moisture.
If using welding equipment or pressure
washing equipment in the vicinity of the
module, take care not to direct heat, or jets of
water or steam at the module. If this cannot be
avoided, remove the module from the vehicle,
and protect its wiring plug with a plastic bag.
Before disconnecting any wiring, or
removing components, always ensure that the
ignition is switched off.
On models with underbonnet-mounted
modules, do not run the engine with the module
detached from the body panel, as the body acts
as an effective heat sink, and the module may
be damaged due to internal overheating.
Do not attempt to improvise fault diagnosis
procedures using a test lamp or multimeter,
as irreparable damage could be caused to the
module.
After working on ignition/engine
management system components, ensure
that all wiring is correctly reconnected before
reconnecting the battery or switching on the
ignition.
On some early Bosch distributors it is
possible that with the distributor cap removed,
if the engine is cranked, the cap securing clips
may fall inward and jam the trigger
wheel/vane, knocking it out of alignment. If this
happens, the distributor will have to be
renewed as the trigger wheel/vane cannot be
repositioned. Care should therefore be taken
not to crank the engine with the distributor cap
removed. Later distributors have redesigned
clips which eliminate the problem.
Removal
1The battery is located in the engine
compartment on the left-hand side of the
bulkhead.
2Disconnect the leads at the negative (earth)
terminal by unscrewing the retaining nut and
removing the bulb. Pull off the plastic cover,
and disconnect the positive terminal leads in
the same way.
3Unscrew the clamp bolt sufficiently to
enable the battery to be lifted from its location
(see illustration). Keep the battery in an
upright position to avoid spilling electrolyte on
the bodywork.
Refitting
4Refitting is a reversal of removal, but smear
petroleum jelly on the terminals when
reconnecting the leads, and always connect
the positive lead first and the negative lead last.
Testing
Standard and low maintenance battery
1If the vehicle covers a small annual mileage
it is worthwhile checking the specific gravity
of the electrolyte every three months to
determine the state of charge of the battery.
Use a hydrometer to make the check and
compare the results with the following table.
Ambient temperature:
above 25ºCbelow 25ºC
Fully charged1.21 to 1.231.27 to 1.29
70% charged1.17 to 1.191.23 to 1.25
Fully discharged1.05 to 1.071.11 to 1.13
Note that the specific gravity readings assume
an electrolyte temperature of 15ºC (60ºF); for
every 10ºC (50ºF) below 15ºC (60ºF) subtract
0.007. For every 10ºC(50ºF) above 15ºC(60ºF)
add 0.007.
2If the battery condition is suspect first
check the specific gravity of electrolyte in
each cell. A variation of 0.040 or more
between any cells indicates loss of electrolyte
or deterioration of the internal plates.
3If the specific gravity variation is 0.040 or
more, the battery should be renewed. If the
cell variation is satisfactory but the battery is
discharged, it should be charged as
described later in this Section.
Maintenance-free battery
4In cases where a “sealed-for-life”
maintenance-free battery is fitted, topping-up
and testing of the electrolyte in each cell is not
possible. The condition of the battery can
therefore only be tested using a battery
condition indicator or a voltmeter.
5If testing the battery using a voltmeter,
connect the voltmeter across the battery and
compare the result with those given in theSpecifications under “charge condition”. The
test is only accurate if the battery has not
been subject to any kind of charge for the
previous six hours. If this is not the case,
switch on the headlights for 30 seconds, then
wait four to five minutes before testing the
battery after switching off the headlights. All
other electrical components must be switched
off, so check that the doors and tailgate are
fully shut when making the test.
6If the voltage reading is less than 12.2 volts,
then the battery is discharged, whilst a
reading of 12.2 to 12.4 volts indicates a
partially discharged condition.
7If the battery is to be charged, first remove
it from the vehicle.
Charging
Standard and low maintenance battery
8Charge the battery at a rate of 3.5 to 4
amps and continue to charge the battery at
this rate until no further rise in specific gravity
is noted over a four hour period.
9Alternatively, a trickle charger charging at the
rate of 1.5 amps can be safely used overnight.
10Specially rapid “boost” charges which are
claimed to restore the power of the battery in
1 to 2 hours are not recommended as they
can cause serious damage to the battery
plates through overheating.
11While charging the battery, note that the
temperature of the electrolyte should never
exceed 37.8ºC (100ºF).
Maintenance-free battery
12This battery type takes considerably
longer to fully recharge than the standard
type, the time taken being dependent on the
extent of discharge, but it can take anything
up to three days.
13A constant voltage type charger is
required, to be set, when connected, to 13.9
to 14.9 volts with a charger current below 25
amps. Using this method the battery should
be useable within three hours, giving a voltage
reading of 12.5 volts, but this is for a partially
discharged battery and, as mentioned, full
charging can take considerably longer.
14If the battery is to be charged from a fully
discharged state (condition reading less than
12.2 volts) have it recharged by your Ford
dealer or local automotive electrician as the
charge rate is higher and constant supervision
during charging is necessary.
3Battery - testing and charging
2Battery - removal and refitting
Engine electrical systems 5•5
5
2.3 Battery securing clamp and bolt
Warning: The HT voltage
generated by an electronic
ignition system is extremely
high, and in certain
circumstances could prove fatal. Take care
to avoid receiving electric shocks from the
HT side of the ignition system. Do not
handle HT leads, or touch the distributor
or coil when the engine is running. If
tracing faults in the HT circuit, use well
insulated tools to manipulate live leads.

38Before refitting the sensor, examine the
O-ring, and renew it if damaged or worn.
39Refitting is a reversal of removal, noting
the torque setting for the sensor screw.
Note: Procedures for removal and refitting of
the ignition system components and
electronic module are given elsewhere in the
relevant Sections of this Chapter.
1Disconnect the battery negative lead.
Crankshaft speed/position sensor
2The sensor is mounted in a bracket on the
timing cover.
3Disconnect the sensor wiring plug by
pulling on the plug, not the wiring (see
illustration).
4Slacken the sensor clamping screw and
slide the sensor from its bracket.
5Refitting is a reversal of removal, but the
clearance between the sensor and the
toothed wheel on the crankshaft must be set
at 1.0 mm (0.04 in). This can be achieved by
inserting a suitable length of wire or rod with a
diameter of 1.0 mm (0.04 in) between the
sensor and the toothed wheel (see
illustration). Do not overtighten the clamping
screw, as damage to the sensor may result.
Engine coolant temperature
sensor
6The sensor is located in the side of the inlet
manifold(see illustration).
7Partially drain the cooling system.
8Disconnect the sensor wiring plug by
pulling on the plug, not the wiring.
9Unscrew the sensor from the inlet manifold
and remove it.
10Refitting is a reversal of removal. Fill the
cooling system.
Air charge temperature sensor
11The sensor is located in the base of the air
cleaner.
12Remove the air cleaner.
13Disconnect the sensor wiring plug by
pulling on the plug, not the wiring (see
illustration).14Unscrew the sensor from the air cleaner
using a suitable spanner.
15Refitting is a reversal of removal. Refit the
air cleaner. Ensure that the vacuum hose is
securely connected.
Electric choke heater
16The electric choke heater is an integral
part of the automatic choke housing on the
carburettor. Removal and refitting of the
choke housing is covered in Chapter 4.
17The operation of the electric choke heater
relay can be checked by starting the engine
from cold, and placing a finger on the relay
(see illustration). It should be possible to feel
the relay switching on and off. If this is not the
case, renew the relay.
Throttle damper control solenoid
18The solenoid is on the right-hand side of
the engine compartment (see illustration). 19Disconnect the solenoid wiring plug by
pulling on the plug, not the wiring.
20Disconnect the two vacuum pipes from
the solenoid, noting their locations for use
when refitting.
21Remove the securing screw and withdraw
the solenoid from the body panel.
22Refitting is a reversal of removal, but note
that the locating lug on the solenoid bracket
should engage with the body panel, and make
sure that the vacuum pipes are correctly
connected.
Throttle damper
23Remove the air cleaner.
24Disconnect the vacuum pipe from the
throttle damper.
20ESC Hybrid system
components - removal and
refitting
5•22Engine electrical systems
20.3 Disconnecting crankshaft
speed/position sensor wiring plug - ESC
Hybrid system
20.6 Engine coolant temperature sensor
location - ESC Hybrid system
20.25 Throttle damper assembly - ESC
Hybrid system
A Securing screws
B Adjusting screwC Throttle lever20.18 Throttle damper control solenoid -
ESC Hybrid system20.17 Electric choke heater relay location
(arrowed) in main fusebox - ESC Hybrid
system
20.13 Disconnecting air charge
temperature sensor wiring plug - ESC
Hybrid system
20.5 Setting the gap between the crankshaft
speed/position sensor and the crankshaft
toothed wheel - ESC Hybrid system

25Remove the two securing screws and
detach the throttle damper and bracket
assembly from the carburettor (see
illustration).
26Commence refitting by securing the
throttle damper and bracket assembly to the
carburettor with the two screws. Ensure that
the throttle lever is correctly positioned in the
slot in the throttle damper actuating arm.
27Reconnect the vacuum pipe to the throttle
damper.
28Reconnect the air cleaner vacuum hose to
the inlet manifold, and reconnect the air
change temperature sensor wiring plug, then
place the air cleaner to one side to allow
access to the throttle damper.
29Reconnect the battery negative lead.
30Connect a tachometer to the engine in
accordance with the manufacturer’s
instructions.
31Start the engine, then check and if
necessary adjust the idle speed and mixture.
32Earth the “service adjustment” lead,
located in the battery negative wiring loom
(see illustration), for a minimum of 10
seconds. The throttle damper actuating arm
should move to the fully retracted position,
raising the engine speed.
33The engine speed should stabilise at 1700
±100 rpm. If adjustment is necessary, turn
the adjusting screw on the end of the throttle
damper actuating arm to give the correct
speed. Turn the screw clockwise to increase
the engine speed, or anti-clockwise to reduce
the engine speed.34On completion of adjustment, stop the
engine and disconnect the tachometer.
35Where necessary, ensure that any
tamperproof seals are refitted, then refit the
air cleaner, ensuring that the vacuum hose is
securely connected. Isolate the “service
adjustment” lead.
36Start the engine and check that normal
idle speed is resumed, then stop the engine.
Note:Procedures for removal and refitting of
the ignition system components and
electronic module are given elsewhere in the
relevant Sections of this Chapter.
Engine coolant temperature
sensor
2.0 litre SOHC fuel injection models
1For details of engine coolant temperature
sensor removal and refitting, refer to the
Section appertaining to the ESC II system.
1.6 and 1.8 litre (R6A type) CVH models
2The sensor is located in the side of the inlet
manifold.
3Disconnect the battery negative lead.
4Partially drain the cooling system.
5Disconnect the sensor wiring plug by
pulling on the plug, not the wiring (see
illustration).
6Unscrew the sensor from the inlet manifold
and remove it.
7Refitting is a reversal of removal. Refill the
cooling system.
2.0 litre DOHC fuel injection models
8The sensor is located in the side of the inlet
manifold, behind the throttle body. The
removal and refitting procedure is as
described for the 1.6 and 1.8 litre (R6A type)
CVH models above.
Crankshaft speed/position sensor
1.6 and 1.8 litre (R6A type) CVH
models
1.6 litre
9The sensor is located at the left-hand rear
of the cylinder block, above the starter motor
(see illustration).10Disconnect the battery negative lead.
11Remove the securing screw, and
withdraw the sensor shroud.
12Disconnect the sensor wiring plug.
13Remove the Torx securing screw, and
withdraw the sensor.
14Refitting is a reversal of removal.
1.8 litre
15Proceed as described for the ESC Hybrid
module. If a new sensor (not the original unit)
is being fitted, position it in the mounting
bracket so that it is in actual contact with one
of the teeth of the toothed wheel on the
crankshaft. Hold the sensor in this position,
and tighten the clamping screw. New sensors
have projections on their base, which will
wear away when the engine is cranking, and
automatically set the specified clearance.
2.0 litre DOHC fuel injection models
16This procedure is as described for the 2.0
litre DOHC carburettor models (ESC II
module).
Air charge temperature sensor
1.6 and 1.8 litre (R6A type) CVH
models
17The sensor is located in the side of the
CFI unit on 1.6 litre engines (see illustration),
and on the inlet manifold on 1.8 litre engines.
18Disconnect the battery negative lead.
19Disconnect the sensor wiring plug by
pulling on the plug, not the wiring.
20Unscrew the sensor from its location, and
remove it.
21Refitting is a reversal of removal, but coat
the threads of the sensor with suitable sealant
before fitting.
2.0 litre DOHC fuel injection models
22The sensor is located in the upper section
of the inlet manifold.
23Disconnect the battery negative lead.
24Disconnect the sensor wiring plug by
pulling on the plug, not the wiring (see
illustration).
25Unscrew the sensor from the inlet
manifold, and remove it.
26Refitting is a reversal of removal, noting
the torque setting for the sensor.
21EEC IV system components -
removaland refitting
Engine electrical systems 5•23
5
21.9 Crankshaft speed/position sensor
(arrowed) viewed from front of engine with
shroud removed21.17 Air charge temperature sensor
location on 1.6 litre engines (arrowed)
21.5 Disconnecting the engine coolant
temperature sensor wiring plug20.32 Service adjustment lead location
(arrowed) - ESC Hybrid system