1993 FORD MONDEO fuse

3Release the protruding locking lugs on each
union, by squeezing them together and
carefully pulling the coupling apart. Use rag to
soak up any spilt fuel. Where the unions are
colour-coded, the pipes cannot be confused.
Where both unions are the same colour, note
carefully which pipe is connected to which,
and ensure that they are correctly
reconnected on refitting (see illustration).
4To reconnect one of these couplings, press
them together until the locking lugs snap into
their groove. Switch the ignition on and off
five times to pressurise the system, and check
for any sign of fuel leakage around the
disturbed coupling before attempting to start
the engine.
Checking
5Checking procedures for the fuel lines are
included in Chapter 1.
Component renewal
6If you must renew any damaged sections,
use original-equipment replacement hoses or
pipes, constructed from exactly the same
material as the section you are replacing. Do
not install substitutes constructed from
inferior or inappropriate material, or you could
cause a fuel leak or a fire.
7Before detaching or disconnecting any part
of the fuel system, note the routing of all
hoses and pipes, and the orientation of all
clamps and clips. Replacement sections must
be installed in exactly the same manner.8Before disconnecting any part of the fuel
system, be sure to relieve the fuel system
pressure (see Section 2), and equalise tank
pressure by removing the fuel filler cap. Also
disconnect the battery negative (earth) lead -
see Chapter 5, Section 1. Cover the fitting
being disconnected with a rag, to absorb any
fuel that may spray out.
Air cleaner assembly
1Disconnect the battery negative (earth) lead
- see Chapter 5, Section 1.
2Unclip the air mass meter from the air
cleaner cover (see Chapter 6).
3Disconnect the crankcase breather hose,
either from the air cleaner housing or from the
cylinder head cover union (see illustration).
4Remove the rubber retaining band (see
illustration). Withdraw the air cleaner
assembly, lifting it upwards out of its
grommets, and releasing it from the rubber
connector sleeve in the inner wing panel.
5Refitting is the reverse of the removal
procedure. Ensure that the housing pegs seat
correctly in their grommets, and that the
intake mouth is fully engaged inside the
connector sleeve (see illustration).
Air intake components
Note:Depending on the reason for removal,
these components can be removed either
individually, or as one assembly. For example,
unplugging the two electrical connectors and
disconnecting the vacuum hose (where fitted),
will allow the air cleaner assembly cover to be
removed with the air mass meter, the
resonator and the plenum chamber.
Air mass meter
6Refer to Section 4 of Chapter 6.
Resonator (engine compartment)
7Unbolt the resonator support bracket from
the engine compartment front crossmember.
Slacken the two clamp screws securing the
resonator to the air mass meter and plenum
chamber hoses. Swing the resonator clear of
the thermostat housing, and unplug the intake
air temperature sensor’s electrical connector
(see illustration). Withdraw the resonator.
8Refitting is the reverse of the removal
procedure.
Plenum chamber
9Prising out the rubber plugs covering them,
undo the chamber’s fasteners (see
illustration). Slacken the clamp screw
securing the chamber to the resonator hose.
10Lift the chamber and (where fitted)
disconnect the vacuum hose from its
underside. Withdraw the chamber - note the
two rubber spacers (one on each throttle
4 Air cleaner assembly and air
intake components -
removal and refitting
Fuel and exhaust systems 4•3
4
4.5 Ensure air filter housing intake mouth
is fully engaged inside connector sleeve4.7 Unplugging intake air temperature
sensor’s electrical connector4.9 Plenum chamber fasteners (arrowed) -
four shown here, some vehicles may only
have three
3.3 Disconnect fuel line quick-release
couplings by squeezing together protruding
locking lugs and pulling coupling apart4.3 Disconnecting the crankcase breather
hose from the cylinder head union4.4 Remove rubber retaining band to
withdraw air cleaner assembly
procarmanuals.com

which pulley, disconnect the first cable end
nipple from the throttle actuator’s upper
pulley, then slide the cable outer upwards out
of the actuator housing. Disconnect the
second cable in the same way from the
actuator’s lower pulley.
6Working in the passenger compartment,
reach up to the top of the accelerator pedal.
Pull the end fitting and collar out of the pedal,
then release the cable inner wire through the
slot in the pedal. Tie a length of string to the
end of the cable.
7Returning to the engine compartment, pull
the cable through the bulkhead until the string
can be untied and the pedal-to-actuator cable
removed.
Refitting
8Refitting is the reverse of the removal
procedure. Use the string to draw the pedal-
to-actuator cable through the bulkhead.
Ensure that each cable end is connected to
the correct actuator pulley.
9Adjust both cables as described below.
Adjustment
Note:Both sections of the cable must be
adjusted together, even if only one has been
disturbed.
10Remove the plenum chamber (see
Section 4).
11Remove the metal clip from the adjuster
of each cable section (see illustration), and
lubricate the adjusters’ grommets with soapy
water.
12Remove any slack by pulling both cable
outers as far as possible out of their
respective adjusters.
13Unplug the TCS throttle actuator’s
electrical connector, and prise off its cover.
Lock both pulleys together by pushing a
locking pin (a pin punch or a similar tool of
suitable size) into their alignment holes.
Disconnect the actuator-to-throttle housing
cable’s end nipple from the throttle linkage.
14Have an assistant depress the accelerator
pedal fully. The pedal-to-actuator cable outer
will move back into the adjuster; hold it there,
and refit the clip.
15Connect the actuator-to-throttle housing
cable end nipple to the throttle linkage, andcheck that the cable outer’s grommet is
correctly secured in the housing bracket.
16Again have the assistant depress the
accelerator pedal fully. The actuator-to-
throttle housing cable outer will move back
into the adjuster; hold it there, and refit the
clip.
17Remove the locking pin from the pulleys.
Check that the throttle valve moves smoothly
and easily from the fully-closed to the fully-
open position and back again, as the
assistant depresses and releases the
accelerator pedal. Re-adjust the cable(s) if
required.
18When the setting is correct, refit the TCS
throttle actuator’s cover and electrical
connector, then refit the plenum chamber (see
Section 4).
1Disconnect the cable inner wire from the
pedal - see Section 5 or 6, as appropriate.
2Undo the retaining nuts and bolt, then
withdraw the pedal assembly (see
illustration).
3Refitting is the reverse of the removal
procedure. Adjust the cable(s) as described in
the relevant Section of this Chapter.
Warning: Petrol is extremely
flammable, so take extra
precautions when you work on
any part of the fuel system. Don’t
smoke, or allow open flames or bare light
bulbs, near the work area. Don’t work in a
garage where a natural gas-type appliance
(such as a water heater or clothes dryer)
with a pilot light is present. If you spill any
fuel on your skin, rinse it off immediately
with soap and water. When you perform
any kind of work on the fuel system, wear
safety glasses, and have a Class B type
fire extinguisher on hand.
Fuel pump operation check
1Switch on the ignition and listen for the fuel
pump (the sound of an electric motor running,
audible from beneath the rear seats). Assuming
there is sufficient fuel in the tank, the pump
should start and run for approximately one or
two seconds, then stop, each time the ignition
is switched on. Note:If the pump runs
continuously all the time the ignition is switched
on, the electronic control system is running in
the backup (or “limp-home”) mode referred to
by Ford as “Limited Operation Strategy” (LOS).
This almost certainly indicates a fault in the
ECU itself, and the vehicle should therefore be
taken to a Ford dealer for a full test of the
complete system, using the correct diagnostic
equipment; do not waste time trying to test the
system without such facilities.
2Listen for fuel return noises from the fuel
pressure regulator. It should be possible to
feel the fuel pulsing in the regulator and in the
feed hose from the fuel filter.
3If the pump does not run at all, check the
fuse, relay and wiring (see Chapter 6).
Fuel pressure check
3A fuel pressure gauge, equipped with an
adaptor to suit the Schrader-type valve on the
fuel rail pressure test/release fitting
(identifiable by its blue plastic cap, and
located on the union of the fuel feed line and
the fuel rail) is required for the following
procedure. If the Ford special tool 29-033 is
available (see Section 2), the tool can be
attached to the valve, and a conventional-type
pressure gauge attached to the tool.
4If using the service tool, ensure that its tap
is turned fully anti-clockwise, then attach it to
the valve. Connect the pressure gauge to the
service tool. If using a fuel pressure gauge
with its own adaptor, connect it in accordance
with its maker’s instructions (see illustration).
5Start the engine and allow it to idle. Note
the gauge reading as soon as the pressure
stabilises, and compare it with the pressure
listed in this Chapter’s Specifications.
(a) If the pressure is high, check for a
restricted fuel return line. If the line is
clear, renew the pressure regulator.
8 Fuel pump/fuel pressure -
check
7 Accelerator pedal -
removal and refitting
Fuel and exhaust systems 4•5
4
6.11 Location of TCS throttle actuator-to-
throttle housing cable adjuster (arrowed)7.2 Removing the accelerator pedal
assembly8.4 A fuel pressure gauge, equipped with
an adaptor to suit the Schrader-type valve
on the fuel rail pressure test/release fitting,
is needed to check fuel pressure
procarmanuals.com

into the inlet ports, just above the inlet valves,
by four fuel injectors. The system also
includes features such as the flushing of fresh
(ie, cold) fuel around each injector on start-up,
thus improving hot starts.
The amount of fuel supplied by the injectors
is precisely controlled by an Electronic
Control Unit (ECU). The ECU uses the signals
derived from the engine speed/crankshaft
position sensor and the camshaft position
sensor, to trigger each injector separately in
cylinder firing order (sequential injection), with
benefits in terms of better fuel economy and
lower exhaust emissions.
Air induction system
The air system consists of an air filter
housing, an air mass meter, an intake
resonator and plenum chamber, and a throttle
housing. The air mass meter is an information-
gathering device for the ECU; it uses a “hot-
wire” system to send the ECU a constantly-
varying (analogue) voltage signal
corresponding to the volume of air passing
into the engine. Another sensor in the air mass
meter measures intake air temperature. The
ECU uses these signals to calculate the mass
of air entering the engine.
The throttle valve inside the throttle housing
is controlled by the driver, through the
accelerator pedal. As the valve opens, the
amount of air that can pass through the
system increases. The throttle potentiometer
opens further, the air mass meter’s signal
alters, and the ECU opens each injector for a
longer duration, to increase the amount of fuel
delivered to the inlet ports.
Electronic control system
The ECU controls the fuel injection system,
as well as the other sub-systems which make
up the entire engine management system. It
receives signals from a number of information
sensors, which monitor such variables as
intake air mass and temperature, coolant
temperature, engine speed and position,
acceleration/deceleration, and exhaust gas
oxygen content. These signals help the ECU
determine the injection duration necessary for
the optimum air/fuel ratio. These sensors and
associated ECU-controlled relays are located
throughout the engine compartment. For
further information regarding the ECU and its
control of the engine management system,
see Chapter 6.
Idle speed and mixture
adjustment - general
Both the idle speed and mixture are under
the control of the ECU, and cannot be
adjusted. Not only can they not be adjusted,
they cannot even be checked, except with the
use of special diagnostic equipment (see
Chapter 6) - this makes it a task for a Ford
dealer service department. Do notattempt to
“adjust” these settings in any way without
such equipment.
If the idle speed and mixture are thought tobe incorrect, take the vehicle to a Ford dealer
for the complete system to be tested.
On models equipped with a heated
windscreen, an idle-increase solenoid valve is
fitted, which raises the idle speed to
compensate for the increased load on the
engine when the heated windscreen is
switched on. When the valve is open, air from
the plenum chamber bypasses the throttle
housing and idle speed control valve, passing
directly into the inlet manifold through the
union on its left-hand end. The system is
active only for the four minutes that the
heated windscreen circuit is live, and is
supplementary to the main (ECU-controlled)
idle speed regulation.
Warning: Petrol is extremely
flammable, so extra precautions
must be taken when working on
any part of the fuel system. Do
not smoke, or allow open flames or bare
light bulbs, near the work area. Don’t work
in a garage if a natural gas-type appliance
with a pilot light is present. While
performing any work on the fuel system,
wear safety glasses, and have a dry
chemical (Class B) fire extinguisher on
hand. If you spill any fuel on your skin,
rinse it off immediately with soap and
water.
Note: This is an initial check of the fuel delivery
and air induction sub-systems of the engine
management system, to be carried out in
conjunction with the operational check of the
fuel pump (see Section 8), and as part of the
preliminary checks of the complete engine
management system (see Section 3 of
Chapter 6).
1Check the earth wire connections for
tightness. Check all wiring and electrical
connectors that are related to the system.
Loose electrical connectors and poor earths
can cause many problems that resemble
more serious malfunctions.
2Check to see that the battery is fully-
charged. The ECU and sensors depend on an
accurate supply voltage to properly meter the
fuel.
3Check the air filter element - a dirty or
partially-blocked filter will severely impede
performance and economy (see Chapter 1).
4If a blown fuse is found, renew it and see if
it blows again. If it does, search for a short-
circuited wire in the harness related to the
system (see Chapter 6).
5Check the air intake duct from the intake to
the inlet manifold for leaks, which will result in
an excessively-lean mixture. Also check the
condition of the vacuum hoses connected to
the inlet manifold.
6Remove the plenum chamber from the
throttle housing. Check the throttle valve for
dirt, carbon or other residue build-up. If it’sdirty, seek the advice of a Ford dealer - since
the electronic control system is designed to
compensate for factors such as the build-up
of dirt in the throttle housing, it may well be
best to leave it dirty, unless the deposits are
extensive. Note: A warning label on the
housing states specifically that the housing
bore and the throttle valve have a special
coating, and must not be cleaned using
carburettor cleaner, as this may damage it.
7With the engine running, place a
screwdriver or a stethoscope against each
injector, one at a time. Listen through the
screwdriver handle or stethoscope for a
clicking sound, indicating operation.
8If an injector isn’t operating (or sounds
different from the others), turn off the engine,
and unplug the electrical connector from the
injector. Check the resistance across the
terminals of the injector, and compare your
reading with the resistance value listed in this
Chapter’s Specifications. If the resistance
isn’t as specified, renew the injector.
9A rough idle, diminished performance
and/or increased fuel consumption could also
be caused by clogged or fouled fuel injectors.
Fuel additives that can sometimes clean
fouled injectors are available at car accessory
shops.
10The remainder of the system checks
should be left to a dealer service department
or other qualified repair specialist, as there is
a chance that the ECU may be damaged if
tests are not performed properly.
Warning: The fuel system
pressure must be released before
any part of the system is
disturbed - see Section 2. Petrol
is extremely flammable, so take extra
precautions when you work on any part of
the fuel system. Don’t smoke, or allow
open flames or bare light bulbs, near the
work area. Don’t work in a garage where a
natural gas-type appliance (such as a
water heater or clothes dryer) with a pilot
light is present. If you spill any fuel on your
skin, rinse it off immediately with soap and
water. When you perform any kind of work
on the fuel system, wear safety glasses,
and have a Class B type fire extinguisher
on hand.
Throttle housing
Check
1Remove the plenum chamber (see Sec-
tion 4), and verify that the throttle linkage
operates smoothly.
2If the housing bore and valve are dirty
enough for you to think that this might be the
cause of a fault, seek the advice of a Ford
dealer. Do notclean the housing (see the
notes in the checking procedure given in
Section 15).
16 Fuel system components-
check and renewal
15 Fuel injection system/engine
management system - check
Fuel and exhaust systems 4•9
4
procarmanuals.com

5Undo the sensor’s retaining screw and
withdraw the sensor. The sensor’s bracket
cannot be unbolted from the cylinder
block/crankcase unless the transmission and
flywheel/driveplate have been removed (see
Chapter 2).
6Refitting is the reverse of the removal
procedure.
General information
The charging system includes the
alternator, an internal voltage regulator, a no-
charge (or “ignition”) warning light, the
battery, and the wiring between all the
components. The charging system supplies
electrical power for the ignition system, the
lights, the radio, etc. The alternator is driven
by the auxiliary drivebelt at the front (right-
hand end) of the engine.
The purpose of the voltage regulator is to
limit the alternator’s voltage to a preset value.
This prevents power surges, circuit overloads,
etc., during peak voltage output.
The charging system doesn’t ordinarily
require periodic maintenance. However, the
drivebelt, battery and wires and connections
should be inspected at the intervals outlined
in Chapter 1.
The dashboard warning light should come
on when the ignition key is turned to positions
“II” or “III”, then should go off immediately the
engine starts. If it remains on, or if it comes on
while the engine is running, there is a
malfunction in the charging system (see
Section 11). If the light does not come on
when the ignition key is turned, and the bulb is
sound (see Chapter 12), there is a fault in the
alternator.
Precautions
Be very careful when making electrical
circuit connections to a vehicle equipped with
an alternator, and note the following:
(a) When reconnecting wires to the alternator
from the battery, be sure to note the
polarity.
(b) Before using arc-welding equipment to
repair any part of the vehicle, disconnect
the wires from the alternator and the
battery terminals.
(c) Never start the engine with a battery
charger connected.
(d) Always disconnect both battery leads
before using a battery charger.
(e) The alternator is driven by an engine
drivebelt which could cause serious injury
if your hand, hair or clothes become
entangled in it with the engine running.
(f) Because the alternator is connected
directly to the battery, it could arc or
cause a fire if overloaded or shorted-out.
(g) Wrap a plastic bag over the alternator,
and secure it with rubber bands, beforesteam-cleaning or pressure-washing the
engine.
(h) Never disconnect the alternator terminals
while the engine is running.
1If a malfunction occurs in the charging
circuit, don’t automatically assume that the
alternator is causing the problem. First check
the following items:
(a) Check the tension and condition of the
auxiliary drivebelt - renew it if it is worn or
deteriorated (see Chapter 1).
(b) Ensure the alternator mounting bolts and
nuts are tight.
(c) Inspect the alternator wiring harness and
the electrical connections at the
alternator; they must be in good
condition, and tight.
(d) Check the large main fuses in the engine
compartment (see Chapter 12). If any is
blown, determine the cause, repair the
circuit and renew the fuse (the vehicle
won’t start and/or the accessories won’t
work if the fuse is blown).
(e) Start the engine and check the alternator
for abnormal noises - for example, a
shrieking or squealing sound may indicate
a badly-worn bearing or brush.
(f) Make sure that the battery is fully-charged
- one bad cell in a battery can cause
overcharging by the alternator.
(g) Disconnect the battery leads (negative
first, then positive). Inspect the battery
posts and the lead clamps for corrosion.
Clean them thoroughly if necessary (see
Section 3 and Chapter 1). Reconnect the
lead to the negative terminal.
(h) With the ignition and all accessories
switched off, insert a test light between
the battery negative post and the
disconnected negative lead clamp:
(1) If the test light does not come on, re-
attach the clamp and proceed to the next
step.
(2) If the test light comes on, there is a short
in the electrical system of the vehicle. The
short must be repaired before the
charging system can be checked.
(3) To find the short, disconnect the
alternator wiring harness:
(a) If the light goes out, the alternator is
at fault.
(b) If the light stays on, remove each fuse
until it goes out - this will tell you
which component is short-circuited.
2Using a voltmeter, check the battery
voltage with the engine off. It should be
approximately 12 volts.
3Start the engine and check the battery
voltage again. Increase engine speed until the
voltmeter reading remains steady; it should
now be approximately 13.5 to 14.6 volts.
4Switch on as many electrical accessories
(eg the headlights, heated rear window andheater blower) as possible, and check that the
alternator maintains the regulated voltage at
around 13 to 14 volts. The voltage may drop
and then come back up; it may also be
necessary to increase engine speed slightly,
even if the charging system is working
properly.
5If the voltage reading is greater than the
specified charging voltage, renew the voltage
regulator (see Section 13).
6If the voltmeter reading is less than that
specified, the fault may be due to worn
brushes, weak brush springs, a faulty voltage
regulator, a faulty diode, a severed phase
winding, or worn or damaged slip rings. The
brushes and slip rings may be checked (see
Section 13), but if the fault persists, the
alternator should be renewed or taken to an
auto-electrician for testing and repair.
1Disconnect the battery negative (earth) lead
- see Section 1.
2Remove the plenum chamber (see Chap-
ter 4).
3Unscrew the nuts to disconnect the wiring
from the alternator (see illustration). If
additional working clearance is required, undo
the right-hand of the three screws securing
the wiring “rail” to the rear of the inlet
manifold.
4Jack up and support the front right-hand
corner of the vehicle. Remove the auxiliary
drivebelt and the engine oil filter - place a wad
of rag to soak up the spilled oil (see Chap-
ter 1). Rather than refit a used filter, you are
advised to drain the engine oil, and then to fit
a new filter and refill the engine with clean oil
on reassembly. Where an engine oil cooler is
fitted, it may prove necessary to remove this
as well, to provide the clearance necessary to
remove the alternator (see Chapter 2, Part A).
5Unscrew the two bolts securing the power
steering system pipes to the right-hand side
of the front suspension subframe. With the
front wheels in the straight-ahead position,
disconnect the right-hand track rod end from
the steering knuckle (see Chapter 10).
6Remove the mounting bolts and nuts (one
12 Alternator-
removal and refitting
11 Charging system- testing
10 Charging system - general
information and precautions
Engine electrical systems 5•5
5
12.3 Disconnecting alternator wiring
procarmanuals.com

starter motor must be overhauled or renewed.
(Other possibilities are that the starter motor
mounting bolts are very loose, or that teeth
are missing from the flywheel/driveplate ring
gear.)
4If, when the switch is actuated, the starter
motor does not operate at all but the solenoid
clicks, then the problem lies with either the
battery, the main solenoid contacts, or the
starter motor itself (or the engine is seized).
5If the solenoid plunger cannot be heard to
click when the switch is actuated, the battery
is faulty, there is a fault in the circuit, or the
solenoid itself is defective.
6To check the solenoid, connect a fused
jumper lead between the battery (+) and the
ignition switch terminal (the small terminal) on
the solenoid. If the starter motor now
operates, the solenoid is OK, and the problem
is in the ignition switch, selector lever position
sensor (automatic transmission) or in the
wiring.
7If the starter motor still does not operate,
remove it (see Section 16). The brushes and
commutator may be checked (see Sec-
tion 17), but if the fault persists, the motor
should be renewed, or taken to an auto-
electrician for testing and repair.
8If the starter motor cranks the engine at anabnormally-slow speed, first make sure that
the battery is charged, and that all terminal
connections are tight. If the engine is partially
seized, or has the wrong viscosity oil in it, it
will crank slowly.
9Run the engine until normal operating
temperature is reached, then switch off and
disable the ignition system by unplugging the
ignition coil’s electrical connector; remove
fuse 14 to disconnect the fuel pump.
10Connect a voltmeter positive lead to the
battery positive terminal, and connect the
negative lead to the negative terminal.
11Crank the engine, and take the voltmeter
readings as soon as a steady figure is
indicated. Do not allow the starter motor to
turn for more than 15 seconds at a time. A
reading of 10.5 volts or more, with the starter
motor turning at normal cranking speed, is
normal. If the reading is 10.5 volts or more but
the cranking speed is slow, the solenoid
contacts are burned, the motor is faulty, or
there is a bad connection. If the reading is less
than 10.5 volts and the cranking speed is
slow, the starter motor is faulty or there is a
problem with the battery.1Disconnect the battery negative (earth) lead
- see Section 1.
2Remove the air mass meter and resonator -
refer to Chapter 4.
3Unscrew the upper two starter motor
mounting bolts, noting that one also secures
an engine/transmission earth lead (see
illustration).
4Raise the front of the vehicle, and support it
securely on axle stands.
Warning: Do not place any part of
your body under a vehicle when
it’s supported only by a jack!
5Unscrew the nuts to disconnect the wiring
from the starter/solenoid terminals.
6Remove the remaining starter motor
mounting bolt (see illustration). Remove the
starter.
7Refitting is the reverse of the removal
procedure. Tighten the bolts to the specified
torque wrench settings.
Note:This procedure assumes that
replacement brushes of the correct type have
been obtained - at the time of writing, no
individual starter motor components were
available as separate replacement Ford parts.
An auto electrical specialist should be able to
supply parts such as brushes.
The following procedures are for the
Lucas/Magneti Marelli unit fitted to the project
vehicle - the procedure is essentially the same
for the Bosch unit that may be found on other
models.
1Remove the starter motor from the vehicle
(Section 16) (see illustration).
17 Starter motor- brush and
solenoid renewal
16 Starter motor -
removal and refitting
Engine electrical systems 5•7
5
16.3 Unscrew upper two starter motor
mounting bolts (arrowed) from above16.6 Disconnect starter motor wiring (A),
then unscrew remaining mounting bolt (B),
and remove starter motor from beneath
vehicle
17.1 Exploded view of the Bosch DW starter
motor
1 Solenoid
2 Spring
3 Plunger
4 Engaging lever
5 Drive end housing
6 Drive pinion and
clutch
7 Spacer
8 Ring gear and carrier
9 Output shaft and
planet gear unit
10 Circlip11 Screw
12 End cap
13 C-clip
14 Shim
15 Commutator end
housing
16 Brushplate
17 Yoke
18 Rubber block
19 Armature
20 Retaining plate
procarmanuals.com

constantly monitors the oxygen content of the
exhaust gas. If the percentage of oxygen in
the exhaust gas is incorrect, an electrical
signal is sent to the ECU. The ECU processes
this information, and then sends a command
to the fuel injection system, telling it to change
the air/fuel mixture; the end result is an air/fuel
mixture ratio which is constantly maintained
at a predetermined ratio, regardless of driving
conditions. This happens in a fraction of a
second, and goes on almost all the time while
the engine is running - the exceptions are that
the ECU cuts out the system and runs the
engine on values pre-programmed
(“mapped”) into its memory both while the
oxygen sensor is reaching its normal
operating temperature after the engine has
been started from cold, and when the throttle
is fully open for full acceleration.
In the event of a sensor malfunction, a
back-up circuit will take over, to provide
driveability until the problem is identified and
fixed.
Precautions
(a) Always disconnect the power by
uncoupling the battery terminals - see
Section 1 of Chapter 5 - before removing
any of the electronic control system’s
electrical connectors.
(b) When installing a battery, be particularly
careful to avoid reversing the positive and
negative battery leads.
(c) Do not subject any components of the
system (especially the ECU) to severe
impact during removal or installation.
(d) Do not be careless during fault diagnosis.
Even slight terminal contact can invalidate
a testing procedure, and damage one of
the numerous transistor circuits.
(e) Never attempt to work on the ECU, to test
it (with any kind of test equipment), or to
open its cover.
(f) If you are inspecting electronic control
system components during rainy weather,
make sure that water does not enter any
part. When washing the engine
compartment, do not spray these parts or
their electrical connectors with water.
General
The various components of the fuel, ignition
and emissions control systems (not forgetting
the same ECU’s control of sub-systems such
as the radiator cooling fan, air conditioning
and automatic transmission, where
appropriate) are so closely interlinked that
diagnosis of a fault in any one component is
virtually impossible using traditional methods.
Working on simpler systems in the past, the
experienced mechanic may well have been
able to use personal skill and knowledge
immediately to pinpoint the cause of a fault, or
quickly to isolate the fault, by elimination;however, with an engine management system
integrated to this degree, this is not likely to
be possible in most instances, because of the
number of symptoms that could arise from
even a minor fault.
So that the causes of faults can be quickly
and accurately traced and rectified, the ECU
is provided with a built-in self-diagnosis
facility, which detects malfunctions in the
system’s components. When a fault occurs,
three things happen: the ECU identifies the
fault, stores a corresponding code in its
memory, and (in most cases) runs the system
using back-up values pre-programmed
(“mapped”) into its memory; some form of
driveability is thus maintained, to enable the
vehicle to be driven to a garage for attention.
Any faults that may have occurred are
indicated in the form of three-digit codes
when the system is connected (via the built-in
diagnosis or self-test connectors, as
appropriate) to special diagnostic equipment -
this points the user in the direction of the
faulty circuit, so that further tests can pinpoint
the exact location of the fault.
Given below is the procedure that would be
followed by a Ford technician to trace a fault
from scratch. Should your vehicle’s engine
management system develop a fault, read
through the procedure and decide how much
you can attempt, depending on your skill and
experience and the equipment available to
you, or whether it would be simpler to have
the vehicle attended to by your local Ford
dealer. If you are concerned about the
apparent complexity of the system, however,
remember the comments made in the fourth
paragraph of Section 1 of this Chapter; the
preliminary checks require nothing but care,
patience and a few minor items of equipment,
and may well eliminate the majority of faults.
(a) Preliminary checks
(b) Fault code read-out *
(c) Check ignition timing and base idle
speed. Recheck fault codes to establish
whether fault has been cured or not *
(d) Carry out basic check of ignition system
components. Recheck fault codes to
establish whether fault has been cured or
not *
(e) Carry out basic check of fuel system
components. Recheck fault codes to
establish whether fault has been cured or
not *
(f) If fault is still not located, carry out system
test *
Note:Operations marked with an asterisk
require special test equipment.
Preliminary checks
Note:When carrying out these checks to
trace a fault, remember that if the fault has
appeared only a short time after any part of
the vehicle has been serviced or overhauled,
the first place to check is where that work was
carried out, however unrelated it may appear,
to ensure that no carelessly-refitted
components are causing the problem.If you are tracing the cause of a “partial”
engine fault, such as lack of performance, in
addition to the checks outlined below, check
the compression pressures (see Part A of
Chapter 2) and bear in mind the possibility
that one of the hydraulic tappets might be
faulty, producing an incorrect valve clearance.
Check also that the fuel filter has been
renewed at the recommended intervals.
If the system appears completely dead,
remember the possibility that the
alarm/inhibitor system may be responsible.
1The first check for anyone without special
test equipment is to switch on the ignition,
and to listen for the fuel pump (the sound of
an electric motor running, audible from
beneath the rear seats); assuming there is
sufficient fuel in the tank, the pump should
start and run for approximately one or two
seconds, then stop, each time the ignition is
switched on. If the pump runs continuously all
the time the ignition is switched on, the
electronic control system is running in the
back-up (or “limp-home”) mode referred to by
Ford as “Limited Operation Strategy” (LOS).
This almost certainly indicates a fault in the
ECU itself, and the vehicle should therefore be
taken to a Ford dealer for a full test of the
complete system using the correct diagnostic
equipment; do not waste time trying to test
the system without such facilities.
2If the fuel pump is working correctly (or not
at all), a considerable amount of fault
diagnosis is still possible without special test
equipment. Start the checking procedure as
follows.
3Open the bonnet and check the condition
of the battery connections - remake the
connections or renew the leads if a fault is
found (Chapter 5). Use the same techniques
to ensure that all earth points in the engine
compartment provide good electrical contact
through clean, metal-to-metal joints, and that
all are securely fastened. (In addition to the
earth connection at the engine lifting eye and
that from the transmission to the
body/battery, there is one earth connection
behind each headlight assembly, and one
below the power steering fluid reservoir.)
4Referring to the information given in
Chapter 12 and in the wiring diagrams at the
back of this manual, check that all fuses
protecting the circuits related to the engine
management system are in good condition.
Fit new fuses if required; while you are there,
check that all relays are securely plugged into
their sockets.
5Next work methodically around the engine
compartment, checking all visible wiring, and
the connections between sections of the
wiring loom. What you are looking for at this
stage is wiring that is obviously damaged by
chafing against sharp edges, or against
moving suspension/transmission components
and/or the auxiliary drivebelt, by being
trapped or crushed between carelessly-
refitted components, or melted by being
forced into contact with hot engine castings,
3 Diagnosis system -
general information
6•4 Emissions control systems
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24Ford specify the use of their STAR (Self-
Test Automatic Readout) tester; most Ford
dealers should have such equipment, and the
staff trained to use it effectively. The only
alternatives are as follows:
(a) To obtain one of those proprietary readers
which can interpret EEC-IV three-digit
codes - at present, such readers are too
expensive for the DIY enthusiast, but are
becoming more popular with smaller
specialist garages.
(b) To use an analogue voltmeter, whereby
the stored codes are displayed as sweeps
of the voltmeter needle. This option limits
the operator to a read-out of any codes
stored - ie, there is no control of sensors
and/or actuators - but can still be useful in
pinpointing the faulty part of the engine
management system. The display is
interpreted as follows. Each code
(whether fault code or
command/separator) is marked by a
three-to-four second pause - code “538”
would therefore be shown as long (3 to
4 seconds) pause, five fast sweeps of the
needle, slight (1 second) pause, three fast
sweeps, slight pause, eight fast sweeps,
long pause.
(c) Owners without access to such
equipment must take the vehicle to a Ford
dealer, or to an expert who has similar
equipment and the skill to use it.
25Because of the variations in the design of
fault code readers, it is not possible to give
exact details of the sequence of tests; the
manufacturer’s instructions must be followed,
in conjunction with the codes given below.
The following ten paragraphs outline the
procedure to be followed using a version of
the Ford STAR tester, to illustrate the general
principles, as well as notes to guide the owner
using only a voltmeter.
26The vehicle must be prepared by applying
the handbrake, switching off the air
conditioning (where fitted) and any other
electrical loads (lights, heated rear window,
etc), then selecting neutral (manual
transmission) or the “P” position (automatic
transmission). Where the engine is required to
be running, it must be fully warmed-up to
normal operating temperature before the test
is started. Using any adaptors required,
connect the fault code reader to the system
via the (triangular, three-pin) self-test
connector on the right-hand end of the engine
compartment bulkhead (see illustration). If a
voltmeter is being used, connect its positive
lead to the battery positive terminal, and its
negative lead to the self-test connector’s
output terminal, pin 17. Have a pen and paper
ready to write down the codes displayed.
27Set the tester in operation. For the Ford
STAR tester, a display check will be carried
out and the test mode requirements must be
entered. If a voltmeter is being used, connect
a spare length of wire to earth the self-test
connector’s input terminal, pin 48. Be very
careful to ensure that you earth the correctterminal - the one with the white/green wire.
The first part of the test starts, with the
ignition switched on, but with the engine off.
On pressing the “Mem/test” button, the tester
displays “TEST” and the ready code “000”,
followed by a command code “010” - the
accelerator pedal must be fully depressed
within 10 seconds of the command code
appearing, or fault codes “576” or “577” will
appear when they are called up later. If a
voltmeter is being used, code “000” will not
appear (except perhaps as a flicker of the
needle) and “010” will appear as a single
sweep - to ensure correct interpretation of the
display, watch carefully for the interval
between the end of one code and the
beginning of the next, otherwise you will
become confused and misinterpret the read-
out.
28The tester will then display the codes for
any faults in the system at the time of the test.
Each code is repeated once; if no faults are
present, code “111” will be displayed. If a
voltmeter is being used, the pause between
repetitions will vary according to the
equipment in use and the number of faults in
the system, but was found to be
approximately 3 to 4 seconds - it may be
necessary to start again, and to repeat the
read-out until you are familiar with what you
are seeing.
29Next the tester will display code “010”
(now acting as a separator), followed by the
codes for any faults stored in the ECU’s
memory; if no faults were stored, code “111”
will be displayed.
30When prompted by the tester, the
operator must next depress the accelerator
pedal fully; the tester then checks several
actuators. Further test modes include a
“wiggle test” facility, whereby the operator
can check the various connectors as
described in paragraph 19 above (in this case,
any fault will be logged and the appropriate
code will be displayed), a facility for recalling
codes displayed, and a means for clearing the
ECU’s memory at the end of the test
procedure when any faults have been
rectified.
31The next step when using the Ford STAR
tester is to conduct a test with the engine
running. With the tester set in operation (see
paragraph 26 above) the engine is started and
allowed to idle. On pressing the “Mem/test”
button, the tester displays “TEST”, followed
by one of two codes, as follows.
32If warning code “998” appears, followed
by the appropriate fault code, switch off and
check as indicated the coolant temperature
sensor, the intake air temperature sensor, the
air mass meter, the throttle potentiometer
and/or their related circuits, then restart the
test procedure.
33If command code “020” appears, carry
out the following procedure within ten
seconds:
(a) Depress the brake pedal fully.
(b) Turn the steering to full-lock (either way)and centre it again, to produce a signal
from the power steering pressure switch -
if no signal is sent, fault code “521” will
be displayed.
(c) If automatic transmission is fitted, switch
the overdrive cancel button on and off,
then do the same for the
“Economy/Sport” mode switch.
(d) Wait for separator code “010” to be
displayed, then within 10 seconds,
depress the accelerator pedal fully,
increasing engine speed rapidly above
3000 rpm - release the pedal.
34Any faults found in the system will be
logged and displayed. Each code is repeated
once; if no faults are present, code “111” will
be displayed.
35When the codes have been displayed for
all faults logged, the ECU enters its “Service
Adjustment Programme”, as follows:
(a) The programme lasts for 2 minutes.
(b) The idle speed control valve is
deactivated, and the idle speed is set to
its pre-programmed (unregulated) value. If
the appropriate equipment is connected,
the base idle speed can be checked
(note, however, that it is not adjustable).
(c) The ignition timing can be checked if a
timing light is connected (note, however,
that it is not adjustable).
(d) Pressing the accelerator pedal fully at any
time during this period will execute a
cylinder balance test. Each injector in turn
is switched off, and the corresponding
decrease in engine speed is logged -
code “090” will be displayed if the test is
successful.
(e) At the end of the 2 minutes, the
completion of the programme is shown
by the engine speed briefly rising, then
returning to normal idling speed as
the idle speed control valve is
reactivated.
36As with the engine-off test, further test
modes include a “wiggle test” facility,
whereby the operator can check the various
connectors as described in paragraph 19
above (in this case, any fault will be logged
and the appropriate code will be displayed), a
facility for recalling codes displayed, and a
means for clearing the ECU’s memory at the
end of the test procedure when any faults
have been rectified. If equipment other than
the Ford STAR tester is used, the ECU’s
memory can be cleared by disconnecting the
battery - if this is not done, the code will
reappear with any other codes in the event of
subsequent trouble, but remember that other
systems with memory (such as the clock and
audio equipment) will also be affected. Should
it become necessary to disconnect the
battery during work on any other part of the
vehicle, first check to see if any fault codes
have been logged.
37Given overleaf are the possible codes,
their meanings, and where relevant, the action
to be taken as a result of a code being
displayed.
Emissions control systems 6•7
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Code Meaning Action327 EGR system exhaust gas pressure
differential sensor or solenoid valve Check components (Section 6 of this Chapter)
328 EGR system solenoid valve Check component (Section 6 of this Chapter)
332 EGR valve not opening Check component (Section 6 of this Chapter)
334 EGR system solenoid valve Check component (Section 6 of this Chapter)335 EGR system exhaust gas pressure
differential sensor Check component (Section 6 of this Chapter)
336 Exhaust gas pressure too high Check system (Section 6 of this Chapter)337 EGR system exhaust gas pressure
differential sensor or solenoid valve Check components (Section 6 of this Chapter)
338, 339 Coolant temperature sensor Carry out system test (see below)
341 Service connector earthed Unplug connector and repeat test - reconnect on completion
411 Engine speed too low during test Check for air leaks, then repeat test
412 Engine speed too high during test Check for air leaks, then repeat test
413 to 416 Idle speed control valve Check component (Chapter 4, Section 16)
452 Vehicle speed sensor Check component (Section 4 of this Chapter)
511, 512 ECU memory Check whether battery was disconnected, then check fuse 11 - if fault still
exists, renew ECU (Section 6 of this Chapter)
513 ECU reference voltage Carry out system test (see below)
519, 521 Power steering pressure switch not Check component is fitted and connected, then repeat test - if fault still
operated during test exists, carry out system test (see below)
522, 523 Selector lever position sensor Check component (Chapter 7, Part B)
536 Brake on/off switch not activated
during test Repeat test
538 Operator error during test Repeat test
539 Air conditioning switched on during test Switch off and repeat test
542, 543 Fuel pump circuit Carry out system test (see below)
551 Idle speed control valve circuit Carry out system test (see below)
552 Pulse-air system circuit Carry out system test (see below)
556 Fuel pump circuit Check fuel pump relay - if fault still exists, carry out system test (see below)
558 EGR system solenoid valve circuit Carry out system test (see below)
563 Radiator (high-speed) electric
cooling fan relay and/or circuit Carry out system test (see below)564 Radiator electric cooling fan relay
and/or circuit Carry out system test (see below)
565 Charcoal canister-purge solenoid valve Check component (Section 5 of this Chapter)573 Radiator electric cooling fan relay
and/or circuit Carry out system test (see below)
574 Radiator (high-speed) electric
cooling fan relay and/or circuit Carry out system test (see below)575 Fuel pump and/or fuel cut-off
switch circuits Carry out system test (see below)
576, 577 Accelerator pedal not depressed fully during
test procedure - automatic transmission
kickdown not activated Repeat test
621 Automatic transmission shift solenoid 1 circuit Refer to Chapter 7, Part B
622 Automatic transmission shift solenoid 2 circuit Refer to Chapter 7, Part B
624 Automatic transmission electronic
pressure control solenoid Refer to Chapter 7, Part B
625 Automatic transmission electronic
pressure control solenoid circuit Refer to Chapter 7, Part B
629 Automatic transmission torque
converter clutch solenoid Refer to Chapter 7, Part B
634 Selector lever position sensor circuit Check component (Chapter 7, Part B)
635, 637 Automatic transmission fluid temperature sensor Refer to Chapter 7, Part B
639 Automatic transmission speed sensor Refer to Chapter 7, Part B
645 Automatic transmission 1st speed Refer to Chapter 7, Part B
646 Automatic transmission 2nd speed Refer to Chapter 7, Part B
647 Automatic transmission 3rd speed Refer to Chapter 7, Part B
648 Automatic transmission 4th speed Refer to Chapter 7, Part B
653 Automatic transmission overdrive
cancel button and “Economy/Sport”
mode switch not operated during test Repeat test
998 Warning code Check fault(s) indicated by subsequent code(s)
Emissions control systems 6•9
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