1993 FORD MONDEO seat memory

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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Vehicle speed sensor
29Testing of this component is beyond the
scope of the DIY mechanic, and should be left
to a Ford dealer.
Power steering pressure switch
30Unplug the electrical connector from the
sensor.
31Using an ohmmeter, measure the
resistance between the switch terminals. With
the engine switched off, or idling with the
roadwheels in the straight-ahead position,
little or no resistance should be measured.
With the engine running and the steering on
full-lock, the pressure increase in the system
should open the switch contacts, so that
infinite resistance is now measured.
32If the results obtained show the switch to
be faulty, renew it.
Exhaust gas pressure differential
sensor
33Testing of this component is beyond the
scope of the DIY mechanic, and should be left
to a Ford dealer.
Oxygen sensor
34Testing of this component can be done
only by attaching special diagnostic
equipment to the sensor wiring, and checking
that the voltage varies from low to high values
when the engine is running; do notattempt to
“test” any part of the system with anything
other than the correct test equipment. This is
beyond the scope of the DIY mechanic, and
should be left to a Ford dealer.
Removal and refitting
General
35Before disconnecting any of these
components, always disconnect the power by
uncoupling the battery terminals, negative
(earth) lead first - see Section 1 of Chapter 5.
ECU (Electronic Control Unit)
Note:The ECU is fragile. Take care not to
drop it or subject it to any other kind of
impact, and do not subject it to extremes of
temperature, or allow it to get wet.
36Carefully prise the power steering fluid
reservoir upwards out of its clip on the
suspension mounting. Unscrew the ECU
connector’s retaining bolt, and unplug the
connector (see illustrations).
37Working in the passenger compartment,
unscrew the retaining bolt and withdraw the
mounting bracket (see illustration).
38Lifting the ECU to release it from the
bulkhead carrier bracket, withdraw the unit
(see illustration).
39Refitting is the reverse of the removal
procedure. Whenever the ECU (or battery) is
disconnected, the information relating to idle
speed control and other operating values will
be lost from its memory until the unit has re-
programmed itself; until then, there may be
surging, hesitation, erratic idle and a
generally-inferior level of performance. To
allow the ECU to re-learn these values, start
the engine and run it as close to idle speed as
possible until it reaches its normal operatingtemperature, then run it for approximately two
minutes at 1200 rpm. Next, drive the vehicle
as far as necessary - approximately 5 miles of
varied driving conditions is usually sufficient -
to complete the re-learning process.
Air mass meter
40Releasing its wire clip, unplug the meter’s
electrical connector (see illustration).
41Release the clips and lift the air cleaner
cover, then release the two smaller clips and
detach the meter from the cover (see
illustration).
42Slacken the clamp securing the meter to
the resonator hose, and withdraw the meter.
43Refitting is the reverse of the removal
procedure. Ensure that the meter and air
cleaner cover are seated correctly and securely
fastened, so that there are no air leaks.
Crankshaft speed/position sensor
44Refer to Chapter 5.
Camshaft position sensor
45Remove the air mass meter and resonator
(refer to Chapter 4) to gain access to the
sensor (see illustration). Release the fuel
feed and return hoses from their clip.
46Releasing its wire clip, unplug the
sensor’s electrical connector. Remove the
retaining screw, and withdraw the sensor from
the cylinder head; be prepared for slight oil
loss.
47Refitting is the reverse of the removal
procedure, noting the following points:
6•12 Emissions control systems
4.36A Unclip and lift power steering fluid
reservoir - take care not to spill fluid . . .4.36B . . . unscrew bolt (arrowed) to
release ECU’s electrical connector4.37 Unscrew retaining bolt and withdraw
ECU’s mounting bracket . . .
4.40 Unplugging the air mass meter’s
electrical connector . . .4.38 . . . then lift ECU to disengage it, and
withdraw it4.41 . . . release clips to separate meter
from air cleaner cover
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Chapter 12 Body electrical system
Air bag clock spring - removal and refitting . . . . . . . . . . . . . . . . . . . 30
Air bag control module - removal and refitting . . . . . . . . . . . . . . . . . 29
Air bag unit (driver’s side) - removal and refitting . . . . . . . . . . . . . . . 28
Anti-theft alarm system - general information . . . . . . . . . . . . . . . . . . 20
Auxiliary warning system - general information and
component renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Battery - check, maintenance and charging . . . . . . . . See Chapter 1
Battery - removal and refitting . . . . . . . . . . . . . . . . . . . See Chapter 5
Bulbs (exterior lights) - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Bulbs (interior lights) - renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Clock - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Compact disc player - removal and refitting . . . . . . . . . . . . . . . . . . . 25
Cruise control system - general information . . . . . . . . . . . . . . . . . . . 21
Electrical fault finding - general information . . . . . . . . . . . . . . . . . . . 2
Electrical system check . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1
Exterior light units - removal and refitting . . . . . . . . . . . . . . . . . . . . . 7
Fuses, relays and timer module - testing and renewal . . . . . . . . . . . 3
General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Headlight beam alignment - checking and adjustment . . . . . . . . . . 8
Headlight levelling motor - removal and refitting . . . . . . . . . . . . . . . 9Horn - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Instrument panel - removal and refitting . . . . . . . . . . . . . . . . . . . . . . 10
Instrument panel components - removal and refitting . . . . . . . . . . . 11
Radio aerial - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Radio/cassette player - coding, removal and refitting . . . . . . . . . . . 23
Radio/cassette player power amplifier - removal and refitting . . . . . 24
Speakers - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Speedometer drive cable - removal and refitting . . . . . . . . . . . . . . . 12
Stop-light switch - removal and refitting . . . . . . . . . . . See Chapter 9
Switches - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Tailgate wiper motor assembly - removal and refitting . . . . . . . . . . . 17
TCS inhibition switch - removal and refitting . . . . . . . . See Chapter 9
Trip computer module - removal and refitting . . . . . . . . . . . . . . . . . 18
Windscreen/tailgate washer system and wiper blade
check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1
Windscreen/tailgate washer system components - removal
and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Windscreen wiper motor and linkage - removal and refitting . . . . . . 16
Wiper arms - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Fuses (auxiliary fusebox in engine compartment)
Note:Fuse ratings and circuits are liable to change from year to year. Consult the handbook supplied with the vehicle, or consult a Ford dealer,
for specific information.
Fuse No Rating Colour Circuit(s) protected
1 80 Black . . . . . . . . . . . . . . . . . . . . . . . . . . Power supply to main fusebox
2 60 Yellow . . . . . . . . . . . . . . . . . . . . . . . . . Radiator electric cooling fans
3 60 Yellow . . . . . . . . . . . . . . . . . . . . . . . . . Diesel engine glow plugs and/or ABS braking system
4 20 Yellow . . . . . . . . . . . . . . . . . . . . . . . . . Ignition system, or ignition and daytime running lights
5 30 Light green . . . . . . . . . . . . . . . . . . . . . . Heated windscreen (left-hand side)
6 30 Light green . . . . . . . . . . . . . . . . . . . . . . Heated windscreen (right-hand side)
7 30 Light green . . . . . . . . . . . . . . . . . . . . . . ABS braking system
8 30 Light green . . . . . . . . . . . . . . . . . . . . . . Air conditioning compressor/heated seats or air conditioning
compressor/daytime running lights
9 20 Light blue . . . . . . . . . . . . . . . . . . . . . . . ECU (petrol), Cold start solenoid (Diesel)
10 20 Light blue . . . . . . . . . . . . . . . . . . . . . . . Ignition switch
11 3 Violet . . . . . . . . . . . . . . . . . . . . . . . . . . ECU memory
12 15 Light blue . . . . . . . . . . . . . . . . . . . . . . . Horn and hazard flasher warning system
13 15 Light blue . . . . . . . . . . . . . . . . . . . . . . . Oxygen sensor
14 15 Light blue . . . . . . . . . . . . . . . . . . . . . . . Fuel pump
15 10 Red . . . . . . . . . . . . . . . . . . . . . . . . . . . Dipped beam headlight (right-hand side)
16 10 Red . . . . . . . . . . . . . . . . . . . . . . . . . . . Dipped beam headlight (left-hand side)
17 10 Red . . . . . . . . . . . . . . . . . . . . . . . . . . . Main beam headlight (right-hand side)
18 10 Red . . . . . . . . . . . . . . . . . . . . . . . . . . . Main beam headlight (left-hand side)
12•1
Easy,suitable for
novice with little
experienceFairly easy,suitable
for beginner with
some experienceFairly difficult,suitable
for competent DIY
mechanicDifficult,suitable for
experienced DIY
mechanicVery difficult,
suitable for expert DIY
or professional
Degrees of difficulty
Specifications Contents
12
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