Ford Mondeo (petrol engines). Manual - part 28

Chapter 5 Engine electrical systems

Alternator - removal and refitting  . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Alternator brushes and voltage regulator - renewal  . . . . . . . . . . . . . 13
Auxiliary drivebelt check and renewal  . . . . . . . . . . . . .

See Chapter 1

Battery - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Battery check, maintenance and charging . . . . . . . . .

See Chapter 1

Battery leads - check and renewal . . . . . . . . . . . . . . . . . . . . . . . . . .

Charging system - general information and precautions . . . . . . . . . 10
Charging system - testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Crankshaft speed/position sensor - checking, removal and refitting

Electronic control system - information and

fault diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

See Chapter 6

Electronic Control Unit (ECU) and system information

sensors - general information . . . . . . . . . . . . . . . . .

See Chapter 6

Engine compartment wiring check . . . . . . . . . . . . . . .

See Chapter 1

General information, precautions and battery disconnection . . . . . .

Ignition coil - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . .

Ignition module (automatic transmission models only) -

removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ignition system - general information and precautions . . . . . . . . . . .

Ignition system - testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ignition timing - checking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Spark plug renewal and HT lead check . . . . . . . . . . . .

See Chapter 1

Starter motor - brush and solenoid renewal  . . . . . . . . . . . . . . . . . . . 17
Starter motor - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . 16
Starting system - general information and precautions  . . . . . . . . . . 14
Starting system - testing  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Battery

Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Lead-acid

Rating - Cold cranking/Reserve capacity . . . . . . . . . . . . . . . . . . . . . . .

500 A/75 RC, 590 A/95 RC, or 650 A/130 RC

Ignition timing

Nominal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10° ± 2° BTDC

Note: Ignition timing is under control of ECU - it may vary constantly at idle speed, and is not adjustable.

Ignition coil

Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

37.0 kilovolts (minimum)

Primary resistances - measured at coil connector terminal pins . . . . . .

0.50 ± 0.05 ohms

Alternator

Type:

Model

Rated output

Bosch unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

NC 14V 60-90A

90A

Mitsubishi unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A004T

90A

Minimum brush length - all types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.0 mm

Regulated voltage @ 4000 (engine) rpm and 3 to 7 amp load - all types .

13.5 to 14.6 volts

Starter motor

Type:

Model

Rated output

Bosch unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.1 or 1.4 kW

Lucas/Magneti Marelli unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

M79

1.0 kW

Minimum brush length - all types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8.0 mm

Commutator minimum diameter:

Bosch units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

32.8 mm

Lucas/Magneti Marelli unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Not available

Armature endfloat:

Bosch units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

0.30 mm

Lucas/Magneti Marelli unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

0.25 mm

Torque wrench settings

lbf ft

Crankshaft speed/position sensor:

Sensor-to-bracket screw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6 to 9

4 to 6

Bracket-to-cylinder block crankcase screw . . . . . . . . . . . . . . . . . . . .

Ignition coil bracket-to-cylinder head screws . . . . . . . . . . . . . . . . . . . .

Alternator mounting bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Starter motor mounting bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5•1

Easy, suitable for
novice with little
experience

Fairly easy, suitable
for beginner with
some experience

Fairly difficult, suitable
for competent DIY
mechanic

Difficult, suitable for
experienced DIY
mechanic

Very difficult,
suitable for expert DIY
or professional

Degrees of difficulty

Specifications

Contents

General information

The engine electrical systems include all

ignition, charging and starting components.
Because of their engine-related functions,
these components are discussed separately
from body electrical devices such as the
lights, the instruments, etc (which are
included in Chapter 12).

Precautions

Always observe the following precautions

when working on the electrical system:
(a) Be extremely careful when servicing

engine electrical components. They are
easily damaged if checked, connected or
handled improperly.

(b) Never leave the ignition switched on for

long periods of time when the engine is
not running.

(c) Don’t disconnect the battery leads while

the engine is running.

(d) Maintain correct polarity when connecting

a battery lead from another vehicle during
jump starting - see the “Booster battery
(jump) starting” section at the front of this
manual.

(e) Always disconnect the negative lead first,

and reconnect it last, or the battery may
be shorted by the tool being used to
loosen the lead clamps (see illustration).

It’s also a good idea to review the safety-

related information regarding the engine
electrical systems located in the “Safety first!”
section at the front of this manual, before
beginning any operation included in this Chapter.

Battery disconnection

Several systems fitted to the vehicle require

battery power to be available at all times, either
to ensure their continued operation (such as
the clock) or to maintain control unit memories
(such as that in the engine management
system’s ECU) which would be wiped if the
battery were to be disconnected. Whenever the

battery is to be disconnected therefore, first
note the following, to ensure that there are no
unforeseen consequences of this action:
(a) First, on any vehicle with central locking, it

is a wise precaution to remove the key
from the ignition, and to keep it with you,
so that it does not get locked in if the
central locking should engage accidentally
when the battery is reconnected!

(b) The engine management system’s ECU will

lose the information stored in its memory -
referred to by Ford as the “KAM” (Keep-
Alive Memory) - when the battery is
disconnected. This includes idling and
operating values, and any fault codes
detected - in the case of the fault codes, if it
is thought likely that the system has
developed a fault for which the
corresponding code has been logged, the
vehicle must be taken to a Ford dealer for
the codes to be read, using the special
diagnostic equipment necessary for this (see
Chapter 6). Whenever the battery is
disconnected, the information relating to idle
speed control and other operating values will
have to be re-programmed into the unit’s
memory. The ECU does this by itself, but
until then, there may be surging, hesitation,
erratic idle and a generally inferior level of
performance. To allow the ECU to relearn
these values, start the engine and run it as
close to idle speed as possible until it
reaches its normal operating temperature,
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 relearning process.

(c) If the battery is disconnected while the

alarm system is armed or activated, the
alarm will remain in the same state when
the battery is reconnected. The same
applies to the engine immobiliser system
(where fitted).

(d) If a trip computer is in use, any

information stored in memory will be lost.

(e) If a Ford “Keycode” audio unit is fitted,

and the unit and/or the battery is
disconnected, the unit will not function
again on reconnection until the correct
security code is entered. Details of this

procedure, which varies according to the
unit and model year, are given in the
“Ford Audio Systems Operating Guide”
supplied with the vehicle when new, with
the code itself being given in a “Radio
Passport” and/or a “Keycode Label” at
the same time. Ensure you have the
correct code before you disconnect the
battery. For obvious security reasons, the
procedure is not given in this manual. If
you do not have the code or details of the
correct procedure, but can supply proof
of ownership and a legitimate reason for
wanting this information, the vehicle’s
selling dealer may be able to help.

Devices known as “memory-savers” (or

“code-savers”) can be used to avoid some of
the above problems. Precise details vary
according to the device used. Typically, it is
plugged into the cigarette lighter, and is
connected by its own wires to a spare battery;
the vehicle’s own battery is then disconnected
from the electrical system, leaving the
“memory-saver” to pass sufficient current to
maintain audio unit security codes and ECU
memory values, and also to run permanently-
live circuits such as the clock, all the while
isolating the battery in the event of a short-
circuit occurring while work is carried out.

Warning: Some of these devices
allow a considerable amount of
current to pass, which can mean

that many of the vehicle’s systems are still
operational when the main battery is
disconnected. If a “memory-saver” is used,
ensure that the circuit concerned is
actually “dead” before carrying out any
work on it!

Note: See also the relevant Sections of
Chapter 1.
1 Disconnect the battery leads, negative
(earth) lead first - see Section 1.
2 Remove the battery hold-down clamp (see
illustrations).
3 Lift out the battery. Be careful - it’s heavy.
4 While the battery is out, inspect the tray for
corrosion (see Chapter 1).

2 Battery - removal and refitting

1 General information,

precautions and battery
disconnection

5•2 Engine electrical systems

1.2 Always disconnect battery - negative

(earth) lead first - to prevent the possibility

of short-circuits

2.2A Unscrew hold-down nuts (one of two

arrowed) . . .

2.2B . . . and withdraw hold-down clamp

to release battery

5 If 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!
6 Refitting is the reverse of the removal
procedure.

Note: See also the relevant Sections of
Chapter 1.
1 Periodically 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.
2 Check 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.
3 When 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).
4 Disconnect 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.
5 If 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.
6 Clean the threads of the solenoid or earth
connection with a wire brush to remove rust
and corrosion.

7 Attach the lead to the solenoid or earth
connection, and tighten the mounting nut/bolt
securely.
8 Before connecting a new lead to the

battery, make sure that it reaches the battery
post without having to be stretched.
9 Connect 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 manuals.

(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).
1 If 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).
2 Crank the engine and watch the end of the
tester to see if bright blue, well-defined sparks
occur.
3 If 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.
4 If no sparks or intermittent sparks occur,
the spark plug lead(s) may be defective -
check them as described in Chapter 1.
5 If 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.
6 The 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

Check

1 Having 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.
2 Unplug 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

Apply a light coat of battery
terminal corrosion inhibitor,
or petroleum jelly, to the
threads, to prevent future

corrosion.

3 Using 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.
4 Disconnect 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.
5 If 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

6 Disconnect the battery negative (earth) lead
- see Section 1.
7 Remove the air mass meter and resonator -
refer to Chapter 4.
8 Unplug 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.
9 Undo 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).
10 The suppressor can be unbolted from the
mounting bracket, if required; note that the
coil and bracket are only available as a single
unit.
11 Refitting is the reverse of the removal

procedure. Ensure that the spark plug (HT)
leads are correctly reconnected, and tighten
the coil screws securely.

Note: See Chapter 6 for component location
illustrations.
1 Disconnect the battery negative (earth) lead
- see Section 1.
2 If better access is required, remove the
resonator (see Chapter 4).
3 Unplug the electrical connector from the
module (see illustration).
4 Remove the retaining screws, and detach
the module from the bulkhead mounting
bracket.
5 Refitting 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 may

vary 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 unleaded petrol. Do not use
leaded petrol at any time in a vehicle equipped
with a catalytic converter.

Checking

1 See Section 4 of Chapter 6.

Removal and refitting

2 Disconnect the battery negative (earth) lead
- see Section 1.
3 Raise 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!

4 Unplug 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 assembly

7.3 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 rating

9.4 Location of crankshaft speed/position

sensor - connector arrowed - in front of

cylinder block/crankcase

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