1993 FORD MONDEO ESP

5If you are renewing the battery, make sure
that you get one that’s identical, with the
same dimensions, amperage rating, cold
cranking rating, etc. Dispose of the old battery
in a responsible fashion. Most local authorities
have facilities for the collection and disposal
of such items - batteries contain sulphuric
acid and lead, and should not be simply
thrown out with the household rubbish!
6Refitting is the reverse of the removal
procedure.
Note:See also the relevant Sections of
Chapter 1.
1Periodically inspect the entire length of
each battery lead for damage, cracked or
burned insulation, and corrosion. Poor battery
lead connections can cause starting problems
and decreased engine performance.
2Check the lead-to-terminal connections at
the ends of the leads for cracks, loose wire
strands and corrosion. The presence of white,
fluffy deposits under the insulation at the lead
terminal connection is a sign that the lead is
corroded and should be renewed. Check the
terminals for distortion, missing clamp bolts,
and corrosion.
3When removing the leads, always
disconnect the negative lead first, and
reconnect it last (see Section 1). Even if only
the positive lead is being renewed, be sure to
disconnect the negative lead from the battery
first (see Chapter 1 for further information
regarding battery lead removal).
4Disconnect the old leads from the battery,
then trace each of them to their opposite
ends, and detach them from the starter
solenoid and earth terminals. Note the routing
of each lead, to ensure correct installation.
5If you are renewing either or both of the old
leads, take them with you when buying new
leads. It is vitally important that you replace
the leads with identical parts. Leads have
characteristics that make them easy to
identify: positive leads are usually red, larger
in cross-section, and have a larger-diameter
battery post clamp; earth leads are usually
black, smaller in cross-section and have a
slightly smaller-diameter clamp for the
negative post.
6Clean the threads of the solenoid or earth
connection with a wire brush to remove rust
and corrosion.
7Attach the lead to the solenoid or earth
connection, and tighten the mounting nut/bolt
securely.
8Before connecting a new lead to thebattery, make sure that it reaches the battery
post without having to be stretched.
9Connect the positive lead first, followed by
the negative lead.
General
The ignition system includes the ignition
switch, the battery, the crankshaft speed/
position sensor, the coil, the primary (low
tension/LT) and secondary (high tension/HT)
wiring circuits, and the spark plugs. On models
with automatic transmission, a separate
ignition module is also fitted, its functions
being incorporated in the ECU on models with
manual transmission. The ignition system is
controlled by the engine management
system’s Electronic Control Unit (ECU). Using
data provided by information sensors which
monitor various engine functions (such as
engine speed and piston position, intake air
mass and temperature, engine coolant
temperature, etc.), the ECU ensures a
perfectly-timed spark under all conditions (see
Chapter 6). Note:The ignition timing is under
the full control of the ECU, and cannot be
adjusted - see Section 8 for further details.
Precautions
When working on the ignition system, take
the following precautions:
(a) Do not keep the ignition switch on for more
than 10 seconds if the engine will not start.
(b) If a separate tachometer is ever required
for servicing work, consult a dealer
service department before buying a
tachometer for use with this vehicle -
some tachometers may be incompatible
with this ignition system - and always
connect it in accordance with the
equipment manufacturer’s instructions.
(c) Never connect the ignition coil terminals
to earth. This could result in damage to
the coil and/or the ECU or ignition module
(whichever is fitted).
(d) Do not disconnect the battery when the
engine is running.
(e) Make sure that the ignition module (where
fitted) is properly earthed.
(f) Refer to the warning at the beginning of
the next Section concerning HT voltage.
Warning: Because of the high
voltage generated by the ignition
system, extreme care should be
taken whenever an operation is performed
involving ignition components. This not
only includes the ignition module/ECU, coil
and spark plug (HT) leads, but related
components such as electrical connectors,
tachometer and other test equipment also.Note: This is an initial check of the “ignition
part” of the main engine management system,
to be carried out as part of the preliminary
checks of the complete engine management
system (see Chapter 6).
1If the engine turns over but won’t start,
disconnect the (HT) lead from any spark plug,
and attach it to a calibrated tester (available at
most automotive accessory shops). Connect
the clip on the tester to a good earth - a bolt
or metal bracket on the engine. If you’re
unable to obtain a calibrated ignition tester,
have the check carried out by a Ford dealer
service department or similar. Any other form
of testing (such as jumping a spark from the
end of an HT lead to earth) is not
recommended, because of the risk of
personal injury, or of damage to the
ECU/ignition module (see notes above and in
Section 4).
2Crank the engine and watch the end of the
tester to see if bright blue, well-defined sparks
occur.
3If sparks occur, sufficient voltage is
reaching the plug to fire it. Repeat the check
at the remaining plugs, to ensure that all leads
are sound and that the coil is serviceable.
However, the plugs themselves may be fouled
or faulty, so remove and check them as
described in Chapter 1.
4If no sparks or intermittent sparks occur,
the spark plug lead(s) may be defective -
check them as described in Chapter 1.
5If there’s still no spark, check the coil’s
electrical connector, to make sure it’s clean
and tight. Check for full battery voltage to the
coil at the connector’s centre terminal. The
coil is earthed through the ECU - do not
attempt to check this. Check the coil itself
(see Section 6). Make any necessary repairs,
then repeat the check again.
6The remainder of the system checks should
be left to a dealer service department or other
qualified repair facility, as there is a chance
that the ECU may be damaged if tests are not
performed properly.
Warning: Because of the high
voltage generated by the ignition
system, extreme care should be
taken whenever an operation is performed
involving ignition components. This not
only includes the ignition module/ECU, coil
and spark plug (HT) leads, but related
components such as electrical connectors,
tachometer and other test equipment also.
Check
1Having checked that full battery voltage is
available at the centre terminal of the coil’s
electrical connector (see Section 5),
disconnect the battery negative (earth) lead -
see Section 1.
2Unplug the coil’s electrical connector, if not
already disconnected.
6 Ignition coil -
removal and refitting
5 Ignition system - testing
4 Ignition system - general
information and precautions
3 Battery leads -
check and renewal
Engine electrical systems 5•3
5
Apply a light coat of battery
terminal corrosion inhibitor,
or petroleum jelly, to the
threads, to prevent future
corrosion.
procarmanuals.com

3Using an ohmmeter, measure the
resistance of the coil’s primary windings,
connecting the meter between the coil’s
terminal pins as follows. Measure first from
one outer pin to the centre pin, then from the
other outer pin to the centre. Compare your
readings with the coil primary resistance listed
in the Specifications Section at the beginning
of this Chapter.
4Disconnect the spark plug (HT) leads - note
their connections or label them carefully, as
described in Chapter 1. Use the meter to
check that there is continuity (ie, a resistance
corresponding to that of the coil secondary
winding) between each pair of (HT) lead
terminals; Nos 1 and 4 terminals are
connected by their secondary winding, as are
Nos 2 and 3. Now switch to the highest
resistance scale, and check that there is no
continuity between either pair of terminals and
the other - ie, there should be infinite
resistance between terminals 1 and 2, or 4
and 3 - and between any terminal and earth.
5If either of the above tests yield resistance
values outside the specified amount, or
results other than those described, renew the
coil. Any further testing should be left to a
dealer service department or other qualified
repair facility.
Removal and refitting
6Disconnect the battery negative (earth) lead
- see Section 1.
7Remove the air mass meter and resonator -
refer to Chapter 4.
8Unplug the electrical connector from each
side of the coil, then disconnect the spark
plug (HT) leads - note their connections or
label them carefully, as described in Chapter
1.
9Undo the two screws securing the EGR
pipe to the coil bracket, then remove the coil
mounting (Torx-type) screws. Withdraw the
coil assembly from the cylinder head (see
illustration).
10The suppressor can be unbolted from the
mounting bracket, if required; note that the
coil and bracket are only available as a single
unit.
11Refitting is the reverse of the removalprocedure. Ensure that the spark plug (HT)
leads are correctly reconnected, and tighten
the coil screws securely.
Note:See Chapter 6 for component location
illustrations.
1Disconnect the battery negative (earth) lead
- see Section 1.
2If better access is required, remove the
resonator (see Chapter 4).
3Unplug the electrical connector from the
module (see illustration).
4Remove the retaining screws, and detach
the module from the bulkhead mounting
bracket.
5Refitting is the reverse of the removal
procedure.
As noted in Section 4, the ignition timing is
controlled entirely by the ECU (acting with the
ignition module, on models with automatic
transmission), and cannot be adjusted. The
value quoted in the Specifications Section of
this Chapter is for reference only, and mayvary significantly if “checked” by simply
connecting a timing light to the system and
running the engine at idle speed.
Not only can the ignition timing not be
adjusted, it cannot be checked either, except
with the use of special diagnostic equipment
(see Chapter 6) - this makes it a task for a
Ford dealer service department.
Owners who are taking their vehicles
abroad should note that the ignition system is
set for the engine to use petrol of 95 RON
octane rating by fitting a “plug-in bridge” to
the service connector on the engine
compartment bulkhead (see illustration).
Removing the “plug-in bridge” retards the
ignition timing - by an unspecified value - to
allow the engine to run on 91 RON fuel. This
grade of fuel is the “Regular” or “Normal”
widely used abroad, but not at present
available in the UK. If you are taking the
vehicle abroad, seek the advice of a Ford
dealer (or of one of the motoring
organisations). This will ensure that you are
familiar with the grades of fuel you are likely to
find (and the sometimes confusing names for
those grades), and that the vehicle is set
correctly at all times for the fuel used. Note:
The octane ratings mentioned above are both,
of course, for unleadedpetrol. Do not use
leaded petrol at any time in a vehicle equipped
with a catalytic converter.
Checking
1See Section 4 of Chapter 6.
Removal and refitting
2Disconnect the battery negative (earth) lead
- see Section 1.
3Raise 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!
4Unplug the sensor’s electrical connector
(see illustration).
9 Crankshaft speed/position
sensor-
checking, removal and refitting
8 Ignition timing - checking
7 Ignition module (automatic
transmission models only) -
removal and refitting
5•4 Engine electrical systems
6.9 Unplug coil electrical connector (A),
suppressor connector (B), and spark
plug/HT leads (C), remove screws (D), then
undo Torx-type screws (E) to release
ignition coil assembly7.3 Separate ignition module is fitted to
automatic transmission models only - note
electrical connector (A) and retaining
screws (B)
8.3 Service connector (A) mounted on
engine compartment bulkhead is fitted with
“plug-in bridge” (B) to set engine to use
(unleaded) petrol of 95 RON octane rating9.4 Location of crankshaft speed/position
sensor - connector arrowed - in front of
cylinder block/crankcase
procarmanuals.com

Torque wrench settingsNm lbf ft
Front caliper bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 89
Rear caliper bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 44
Front caliper guide bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 21
Rear caliper guide bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 30
Rear drum brake backplate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 37
Vacuum servo unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 30
Master cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 17
ABS hydraulic unit to bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 15
Roadwheel nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 63
9•2 Braking system
1.2 Handbrake lever and associated components
1 Handbrake lever
2 Clock spring
3 Handbrake cable
4 Toothed segment and pawl to lock the
handbrake lever5 Fine-toothed segment for the clock spring
6 Pawl for the clock spring
7 Underbody bracket
The braking system is of diagonally-split,
dual-circuit design, with ventilated discs at
the front, and drum or disc brakes (according
to model) at the rear. The front calipers are of
floating single-piston design, using asbestos-
free pads. The rear drum brakes are of the
leading and trailing shoe type. They are self-
adjusting during footbrake operation. The rear
brake shoe linings are of different
thicknesses, in order to allow for the different
proportional rates of wear.
Pressure-control relief (PCR) valves are
fitted to the rear brakes, to prevent rear wheel
lock-up under hard braking. The valves are
sometimes referred to as pressure-conscious
reducing valves. On non-ABS models, theyare fitted in the master cylinder rear brake
outlet ports; on ABS models, they are located
on the ABS unit.
When rear disc brakes are fitted, the rear
brake caliper is located on the front of the
knuckle on Saloon and Hatchback models,
and on the rear of the knuckle on Estate
models (see illustration).
The handbrake is cable-operated, and acts
on the rear brakes. On rear drum brake
models, the cables operate on the rear trailing
brake shoe operating levers, and on rear disc
brake models, they operate on levers on the
rear calipers. The handbrake lever
incorporates an automatic adjuster, which
removes any slack from the cables when the
lever is disengaged (see illustration).
Handbrake lever movement remains
consistent at all times, and no adjustment is
necessary or possible.
Where fitted, the anti-lock braking system
(ABS) is of the four-channel low-pressure type
(see illustration). It uses the basic
conventional brake system, together with aBendix ABS hydraulic unit fitted between the
master cylinder and the four wheel brakes.
The hydraulic unit consists of a hydraulic
actuator, an ABS brake pressure pump, an
ABS module with built-in relay box, and two
pressure-control relief valves. Braking at each
of the four wheels is controlled by separate
solenoid valves in the hydraulic actuator. If
wheel lock-up is detected on a wheel when
the vehicle speed is above 3 mph, the valve
opens, releasing pressure to the relevant
brake, until the wheel regains a rotational
speed corresponding to the speed of the
vehicle. The cycle can be repeated many
times a second. In the event of a fault in the
ABS system, the conventional braking system
is not affected. Diagnosis of a fault in the ABS
system requires the use of special equipment,
and this work should therefore be left to a
Ford dealer. Diagnostic connectors are
located on the side of the left-hand front
suspension turret.
The traction control system (TCS) is fitted
as an option to some models, and uses the
1 General information
1.1 Rear disc brake location on
Saloon/Hatchback models (A) and Estate
models (B)
1 Handbrake cable lever facing away from
caliper
2 Handbrake cable lever facing towards
caliper
3 Brake hose banjo bolt
4 Front of vehicle
procarmanuals.com

basic ABS system, with an additional pump
and valves fitted to the hydraulic actuator (see
illustration). If wheelspin is detected at a
speed below 30 mph, one of the valves
opens, to allow the pump to pressurise the
relevant brake, until the spinning wheel slows
to a rotational speed corresponding to the
speed of the vehicle. This has the effect of
transferring torque to the wheel with mosttraction. At the same time, the throttle plate is
closed slightly, to reduce the torque from the
engine. At speeds above 30 mph, the TCS
operates by throttle plate adjustment only.
Warning: Disc brake pads must
be renewed on both front wheels
at the same time - never renew
the pads on only one wheel, as
uneven braking may result. Although
genuine Ford linings are asbestos-free, the
dust created by wear of non-genuine pads
may contain asbestos, which is a health
hazard. Never blow it out with compressed
air, and don’t inhale any of it. DO NOT use
petroleum-based solvents to clean brake
parts; use brake cleaner or methylated
spirit only. DO NOT allow any brake fluid,
oil or grease to contact the brake pads or
disc. Also refer to the warning at the start
of Section 15 concerning brake fluid.
1Apply the handbrake. Loosen the front
wheel nuts, jack up the front of the vehicle
and support it on axle stands.
2Remove the front wheels. Work on onebrake assembly at a time, using the
assembled brake for reference if necessary.
3Follow the accompanying photos,
beginning with illustration 2.3A, for the pad
removal procedure. Be sure to stay in order,
and read the caption under each illustration.
4Inspect the front brake disc for scoring and
cracks. If a detailed inspection is necessary,
refer to Section 4.
5The piston must be pushed back into the
2 Front brake pads - renewal
Braking system 9•3
9
1.4 Solenoid valves fitted to the ABS/TCS
hydraulic actuator
1 ABS/TCS actuator
2 ABS solenoid valves
3 TCS solenoid valves
1.3 Anti-lock Braking System (ABS) and Traction Control System (TCS) component locations (left-hand-drive shown,
right-hand-drive similar)
1 ABS/TCS unit
2 ABS/TCS warning lights
3 TCS switch4 Rear wheel sensor ring location (drum
brakes left, disc brakes right)
5 Stop-light switch6 Self-test/diagnosis connectors
7 Front wheel sensor and ring
8 Throttle actuator
2.3A Prise the retaining clip from the
caliper. Hold it with a pair of pliers, to
avoid personal injury. On models fitted
with pad wear sensors, it will be necessary
to disconnect the wiring
procarmanuals.com

Note:If any part of the ABS hydraulic unit is
defective, it must be renewed as an assembly.
Apart from the relay box (Section 22),
individual spare parts are not available.
Removal
1Remove both pressure-control relief valves
as described in Section 19.
2Identify the location of the remaining brake
hydraulic pipes on the ABS hydraulic unit,
then unscrew the union nuts and pull out the
pipes. Carefully bend the pipes away from the
hydraulic unit, to allow the unit to be removed.
3Disconnect the multi-plugs from the
hydraulic unit. To disconnect the main 22-pin
multi-plug, push the locktab, then swivel the
multi-plug outwards and unhook it.
Right-hand drive models
4Have an assistant hold the brake pedal
depressed, then extract the spring clip and
remove the clevis pin securing the servo unit
pushrod to the pedal cross-link arm.
5Remove the vacuum servo unit from the
engine compartment.
Left-hand drive models
6Unscrew the nut securing the pedal
trunnion to the servo unit pushrod inside the
passenger compartment. The nut is located
near the top of the pedal, and is accessible
through an access hole. For improved access,
remove the lower facia panel first.
7Remove the vacuum servo unit, together
with the pushrod, from the engine
compartment. Take care not to damage the
rubber grommet in the bulkhead.
All models
8Unscrew the pump mounting nut.
9Raise the left-hand side of the ABS
hydraulic unit, then swivel the unit out of the
right-hand mounting. Take care not to lose the
bracket studs and insulator ring.
Refitting
10Locate the insulator ring on the pump
end, and fit the stud cap to the insulator ring.
11Lower the ABS hydraulic unit into
position, right-hand end first.
12Fit the right-hand bracket studs onto the
insulators.
13Lower the left-hand end of the ABS
hydraulic unit onto the bracket, then fit and
tighten the pump mounting nut.
Left-hand drive models
14Locate the vacuum servo unit and
pushrod on the bulkhead bracket, taking care
not to damage the rubber grommet.
15Insert the pushrod in the pedal trunnion,
and tighten the nut.
16Refit the lower facia panel if it was
removed.
Right-hand drive models
17Locate the vacuum servo unit and
pushrod on the bulkhead bracket.
18Refit the clevis pin and spring clip
securing the servo unit pushrod to the pedal
cross-link arm.
All models
19Reconnect the multi-plugs to the
hydraulic unit.
20Reconnect the brake pipes to the
hydraulic unit, and tighten the union nuts.
21Refit both pressure-control relief valves,
with reference to Section 20.
Testing
1Checking of the sensors is done before
removal, connecting a voltmeter to the
disconnected sensor multi-plug. Using an
analogue (moving coil) meter is not practical,
since the meter does not respond quickly
enough. A digital meter having an AC facility
may be used to check that the sensor is
operating correctly. To do this, raise the
relevant wheel then disconnect the wiring to
the ABS sensor and connect the meter to it.
Spin the wheel and check that the output
voltage is between 1.5 and 2.0 volts,
depending on how fast the wheel is spun.
Alternatively, an oscilloscope may be used to
check the output of the sensor - an alternating
current will be traced on the screen, of
magnitude depending on the speed of the
rotating wheel.
2If the sensor output is low or zero, renew
the sensor.
Removal
Front wheel sensor
3Apply the handbrake, jack up the front of
the vehicle and support it on axle stands.
Remove the relevant wheel.
4Unscrew the sensor mounting bolt located
on the steering knuckle, and withdraw the
sensor (see illustrations).
5Remove the sensor wiring loom from thesupport brackets on the front suspension
strut and wheel arch.
6Prise out the stud clips, and remove the
Torx screws and screw clips holding the wheel
arch liner in position. Withdraw the liner.
7Disconnect the multi-plug, and withdraw
the sensor and wiring loom.
Rear wheel sensor
8Chock the front wheels, and engage 1st
gear (or “P”). Jack up the rear of the vehicle
and support it on axle stands. Remove the
relevant wheel.
9Unscrew the sensor mounting bolt, located
on the brake backplate (drum brakes) or rear
suspension knuckle (disc brakes), and
withdraw the sensor.
10On disc brake models, prise out the stud
clips, and remove the Torx screws and screw
clips holding the wheel arch liner in position.
Withdraw the liner.
11Disconnect the sensor wiring loom from
the supports on the rear suspension strut (or
knuckle) and wheel arch.
12Working inside the vehicle, lift the rear
seat cushion, then disconnect the multi-plug
for the sensor wiring loom (see illustration).
13Withdraw the sensor and wiring loom
through the rubber grommet in the rear floor.
Refitting
Front and rear wheel sensors
14Refitting is a reversal of the removal
procedure.
Removal
1Disconnect the battery negative (earth) lead
(Chapter 5, Section 1).
2Detach the vacuum hose from the inlet
manifold connection, pressing in the collar to
disengage the tabs, then withdrawing the
collar slowly.
3To improve access, free the heater hose
from its retaining clips, and position it clear of
the relay box.
4Disconect the wiring connector(s) from the
relay box and, where necessary, the speed
sender unit.
22 ABS relay box -
removal and refitting
21 ABS wheel sensor -
testing, removal and refitting
20 ABS hydraulic unit -
removal and refitting
9•14 Braking system
21.4 Unscrew the mounting bolt and
remove the ABS sensor21.12 Rear ABS sensor wiring multi-plug
located beneath the rear seat
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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back again, as an assistant depresses the
accelerator pedal. If the valve shows any sign
of stiffness, sticking or otherwise-inhibited
movement (and the accelerator cable is
known from the previous check to be in good
condition), spray the throttle linkage with
penetrating lubricant, allow time for it to work,
and repeat the check; if no improvement is
obtained, the complete throttle housing must
be renewed (Chapter 4).
15Unclip the air cleaner cover, and check
that the air filter element and the crankcase
ventilation system filter are not clogged or
soaked. (A clogged air filter will obstruct the
intake air flow, causing a noticeable effect on
engine performance; a clogged crankcase
ventilation system filter will inhibit crankcase
“breathing”). Renew or clean the filter(s) as
appropriate; refer to the relevant Sections of
Chapter 1 for further information, if required.
Before refitting the air cleaner cover, check
that the air intake (located under the front left-
hand wing, opening behind the direction
indicator/headlight assembly) is clear. It
should be possible to blow through the intake,
or to probe it (carefully) as far as the rear of
the direction indicator light.
16Start the engine and allow it to idle.
Note:Working in the engine compartment
while the engine is running requires great care
if the risk of personal injury is to be avoided;
among the dangers are burns from contact
with hot components, or contact with moving
components such as the radiator cooling fan
or the auxiliary drivebelt. Refer to “Safety
first!” at the front of this manual before
starting, and ensure that your hands, and long
hair or loose clothing, are kept well clear of hot
or moving components at all times.
17Working from the air intake junction at the
inner wing panel, via the air cleaner assembly
and air mass meter, to the resonator, plenum
chamber, throttle housing and inlet manifold
(and including the various vacuum hoses and
pipes connected to these), check for air leaks.
Usually, these will be revealed by sucking or
hissing noises, but minor leaks may be traced
by spraying a solution of soapy water on to
the suspect joint; if a leak exists, it will be
shown by the change in engine note and the
accompanying air bubbles (or sucking-in of
the liquid, depending on the pressure
difference at that point). If a leak is found at
any point, tighten the fastening clamp and/or
renew the faulty components, as applicable.
18Similarly, work from the cylinder head, via
the manifold (and not forgetting the related
EGR and pulse-air system components) to the
tailpipe, to check that the exhaust system is
free from leaks. The simplest way of doing
this, if the vehicle can be raised and
supported safely and with complete security
while the check is made, is to temporarily
block the tailpipe while listening for the sound
of escaping exhaust gases; any leak should
be evident. If a leak is found at any point,
tighten the fastening clamp bolts and/or nuts,
renew the gasket, and/or renew the faultysection of the system, as necessary, to seal
the leak.
19It is possible to make a further check of
the electrical connections by wiggling each
electrical connector of the system in turn as
the engine is idling; a faulty connector will be
immediately evident from the engine’s
response as contact is broken and remade. A
faulty connector should be renewed to ensure
the future reliability of the system; note that
this may mean the renewal of that entire
section of the loom - see your local Ford
dealer for details.
20Switch off the engine. If the fault is not yet
identified, the next step is to check the
ignition voltages, using an engine analyser
with an oscilloscope - without such
equipment, the only tests possible are to
remove and check each spark plug in turn, to
check the spark plug (HT) lead connections
and resistances, and to check the
connections and resistances of the ignition
coil. Refer to the relevant Sections of
Chapters 1 and 5.
21The final step in these preliminary checks
would be to use an exhaust gas analyser to
measure the CO level at the exhaust tailpipe.This check cannot be made without special
test equipment - see your local Ford dealer for
details.
Fault code read-out
22As noted in the general comments at the
beginning of this Section, the preliminary
checks outlined above should eliminate the
majority of faults from the engine
management system. If the fault is not yet
identified, the next step is to connect a fault
code reader to the ECU, so that its self-
diagnosis facility can be used to identify the
faulty part of the system; further tests can
then be made to identify the exact cause of
the fault.
23In their basic form, fault code readers are
simply hand-held electronic devices, which
take data stored within an ECU’s memory and
display it when required as two- or three-digit
fault codes. The more sophisticated versions
now available can also control sensors and
actuators, to provide more effective testing;
some can store information, so that a road
test can be carried out, and any faults
encountered during the test can be displayed
afterwards.
6•6 Emissions control systems
3.26 Location and terminal identification of engine management system self-test,
diagnosis and service connectors
1 Power steering fluid reservoir
2 Diagnosis connector - for Ford diagnostic equipment FDS 2000
3 Self-test connector - for fault code read-out - pin 17 is output terminal, pin 48 is input
terminal, pin 40/60 is earth
4 Service connector - for octane adjustment
5 Plug-in bridge - to suit 95 RON fuel
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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
6
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