3261 Jaguar XJ6
5
Chapter 5
Engine electrical systems
Ignition system
Ignition timing (all models) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Not adjustable
Ignition coil resistance (at 68°F):
Primary resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.4 to 0.5 ohms
Secondary resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.0 to 6.5 k-ohms
Charging system
Charging voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.9 to 15.1 volts
Standard amperage:
No load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Less than 10 amps
Full load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 amps or more Amplifier - check and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Alternator - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Battery cables - check and renewal . . . . . . . . . . . . . . . . . . . . . . . . . 4
Battery check, maintenance and charging . . . . . . . . . . . See Chapter 1
Battery - emergency jump starting . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Battery - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Charging system - check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Charging system - general information and precautions . . . . . . . . . 10
CHECK ENGINE light . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 6
Distributor - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Drivebelt check, adjustment and renewal . . . . . . . . . . . See Chapter 1General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Ignition coil - check and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Ignition system - check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Ignition system - general information and precautions . . . . . . . . . . . 5
Spark plug renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1
Spark plug lead, distributor cap and rotor check
and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Chapter 1
Starter motor - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . 15
Starter motor - testing in vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Starter solenoid - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . 16
Starting system - general information and precautions . . . . . . . . . . 13
5•1
Specifications Contents
Easy,suitable for
novice with little
experienceFairly easy,suitable
for beginner with
some experienceFairly difficult,
suitable for competent
DIY mechanic
Difficult,suitable for
experienced DIY
mechanicVery difficult,
suitable for expert DIY
or professional
Degrees of difficulty
54321
1 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 chassis electrical devices such as the
fuses, relays, lights, etc. (which are included in
Chapter 12).
Always observe the following precautions
when working on the electrical systems:
a) Be extremely careful when servicing
engine electrical components. They are
easily damaged if checked, connected or
handled improperly.
b) Never leave the ignition switch on for long
periods of time (10 minutes maximum)
with the engine off.c) Don’t disconnect the battery cables while
the engine is running.
d) Maintain correct polarity when connecting
a battery cable from another vehicle
during jump starting.
e) Always disconnect the negative cable first
and hook it up last or the battery may be
shorted by the tool being used to loosen
the cable clamps.
It’s also a good idea to review the safety-
related information regarding the engine
electrical systems in the Safety first section
near the front of this manual before beginning
any operation included in this Chapter.
2 Battery-
emergency jump starting
1
See “Jump starting”in “Roadside repairs”
at the front of this Manual.
3 Battery- removal and refitting
1
1Disconnect the negative terminal, then the
positive terminal from the battery. On 1989 to
1992 models, the battery is located in the
engine compartment on the passenger side
bulkhead and on 1993 and 1994 models, it is
located in the boot.
Caution: If the stereo in your vehicle is
equipped with an anti-theft system, make
sure you have the correct activation code
before disconnecting the battery.
2Remove the battery hold-down clamp.
3Lift out the battery. Be careful, it’s heavy.
4While the battery is out, inspect the carrier
(tray) for corrosion.
5If you are replacing the battery, make sure
that you get one that’s identical, with the
Refitting
7Insert the distributor into the engine in
exactly the same relationship to the block that
it was in when removed.
8If the distributor does not seat completely,
recheck the alignment marks between the
distributor base and the block to verify that
the distributor is in the same position it was in
before removal. Also check the rotor to see if
it’s aligned with the mark you made on the
edge of the distributor base.
9Refit the distributor hold-down bolt(s).
10The remainder of refitting is the reverse of
removal.
10 Charging system- general
information and precautions
The charging system includes the alternator,
an internal voltage regulator, a charge
indicator light, load dump module, the battery,
an ignition ON relay, an in-line fuse and the
wiring between all the components (see
illustration). The charging system supplies
electrical power for the ignition system, the
lights, the radio, etc. The alternator is driven by
a drivebelt at the front 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 alternator load dump module protects
the electrical circuits from excessive voltage
surges. When the battery cables are removed
large amounts of transient voltage is released
through the electrical circuits. This device
diverts up to 30 load volts of excess voltage to
earth by way of a voltage dependent resistor.
The in-line fuse is a special fuse installed
into the circuit with the engine compartment
wiring harness (see Chapter 12). The in-line
fuse protects the electrical system in the
event of excess voltage surges or a power to
earth short circuit. Refer to Chapter 12 for
additional information concerning the in-line
fuses and their locations.
1993 and 1994 models have a Starter Logic
Relay. This microprocessor (computer)
gathers information from the ignition switch,
linear gear position switch, park/neutral
switch, the security switch and the electronic
door lock system. If all the conditions are in
order, the computer allows battery voltage to
be transferred from the ignition switch to the
starter/solenoid assembly.
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 Start,
then should go off immediately. If it remains
on, there is a malfunction in the charging
system. Some vehicles are also equipped with
a voltage gauge. If the voltage gaugeindicates abnormally high or low voltage,
check the charging system (see Section 11).
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, note their 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 before steam
cleaning the engine.
11 Charging system- check
2
Note:1993 and 1994 models are equipped
with a Starter Logic Relay. This microprocessor
(computer) gathers information from theignition switch, linear gear position switch,
park/neutral switch, the security switch and the
electronic door lock system. If all the conditions
are in order, the computer allows battery
voltage to be transferred from the ignition
switch to the starter/solenoid assembly. If all
the components of the charging system are
working properly and the system still does not
charge properly, have the Starter Logic Relay
diagnosed by a dealer service department.
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 drivebelt tension and its
condition. Renew it if worn or damaged.
b) Make sure the alternator mounting and
adjustment bolts are tight.
c) Inspect the alternator wiring harness and
the electrical connectors at the alternator
and voltage regulator. They must be in
good condition and tight.
d) Check the fusible link (if equipped)
located between the starter solenoid and
the alternator or the large main fuses in
the engine compartment. If it’s burned,
determine the cause, repair the circuit
and renew the link or fuse (the vehicle
won’t start and/or the accessories won’t
work if the fusible link or fuse blows).
e) Check all the in-line fuses that are in series
with the charging system circuit (see
Chapter 12).The location of these fuses
and fusible links may vary from year and
Engine electrical systems 5•5
5
10.1 Schematic of a typical charging system
3261 Jaguar XJ6
model but the designations are the same.
Refer to the wiring diagrams at the end of
Chapter 12.
f) Start the engine and check the alternator
for abnormal noises (a shrieking or
squealing sound indicates a bad bushing).
g) Check the specific gravity of the battery
electrolyte. If it’s low, charge the battery
(doesn’t apply to maintenance free
batteries).
h) Make sure that the battery is fully charged
(one bad cell in a battery can cause
overcharging by the alternator).
i) Disconnect the battery cables (negative
first, then positive). Caution:If the stereo
in your vehicle is equipped with an anti-
theft system, make sure you have the
correct activation code before
disconnecting the battery. Inspect the
battery posts and the cable clamps for
corrosion. Clean them thoroughly if
necessary (see Chapter 1). Reconnect the
positive cable, then the negative cable.
2Using a voltmeter, check the battery
voltage with the engine off. It should be
approximately 12 volts (see illustration).
3Start the engine and check the battery
voltage again. It should now be approximately
13.5 to 15.1 volts.
4Turn on the headlights. The voltage should
drop and then come back up, if the charging
system is working properly.
5If the voltage reading is greater than the
specified charging voltage, renew the
alternator.
6If you have an ammeter, connect it up to the
charging system according to its maker’s
instructions. If you don’t have a professional-
type ammeter, you can also use an inductive-
type current indicator. This device is
inexpensive, readily available at car accessory
outlets and accurate enough to perform simple
amperage checks like the following test.7With the engine running at 2000 rpm, check
the reading on the ammeter with all
accessories and lights off (no load), then again
with the high-beam headlights on and the
heater blower switch turned to the HI position
(full load). Compare your readings to the
standard amperage listed in this Chapter’s
Specifications.
8If the ammeter reading is less than standard
amperage, repair or renew the alternator.
9If the alternator is working but the charging
system still does function properly, check the
operation of the load dump module (see
illustration). Have this component checked at
a dealer service department.
12 Alternator-
removal and refitting
2
1Detach the cable from the negative terminal
of the battery.
Caution: If the stereo in your vehicle is
equipped with an anti-theft system, make
sure you have the correct activation code
before disconnecting the battery.2Detach the electrical connectors from the
alternator.
3Loosen the alternator adjustment and pivot
bolts (see illustration) and detach the
drivebelt.
4Remove the adjustment and pivot bolts
(see illustration)from the alternator
adjustment bracket.
5If you are replacing the alternator, take the
old alternator with you when purchasing a
replacement unit. Make sure that the
new/rebuilt unit is identical to the old
alternator. Look at the terminals - they should
be the same in number, size and locations as
the terminals on the old alternator. Finally,
look at the identification markings - they will
be stamped in the housing or printed on a tag
or plaque affixed to the housing. Make sure
that these numbers are the same on both
alternators.
6Many new/rebuilt alternators do not have
a pulley installed, so you may have to switch
the pulley from the old unit to the new/rebuilt
one. When buying an alternator, find out the
policy regarding refitting of pulleys - some
shops will perform this service free of charge.
7Refitting is the reverse of removal.
5•6 Engine electrical systems
12.3 Loosen the lock bolt and back-off
the adjustment bolt (arrowed) to remove
the drivebelt12.4 Remove the pivot bolt and nut
3261 Jaguar XJ6 11.2 Connect the probes of a voltmeter to the battery terminals
and observe battery voltage with the engine OFF
and then with the engine running
11.9 The load dump module is located on the bulkhead
next to the MAF sensor
at a time, so you can use the other side as a
reference during reassembly.
6Refitting is the reverse of removal.
7After refitting the brake disc, adjust the
handbrake shoes. Temporarily refit two nuts,
turn the adjuster (see illustration 5.7c)and
expand the shoes until the disc locks, then
back off the adjuster until you can spin the
disc without the shoes dragging.
8Adjust the handbrake cable (Section 10).
9Remove the axle stands and lower the
vehicle. Tighten the wheel nuts to the specified
torque (see Chapter 1 Specifications).
13 Brake light switch-
check and renewal
1
1The brake light switch activates the brake
lights when the brake pedal is depressed. It‘s
located at the top of the brake pedal, inside
the pedal box.
2If the brake lights don’t come on when the
brake pedal is depressed, check the fuses
(the fuse for the left brake light is in the left
fuse panel and the fuse for the right brake
light is in the right panel).
3If the fuses are okay, check the brake light
bulbs (see Chapter 12).
4If the fuses and bulbs are okay, either the
switch isn’t getting voltage (there’s an open-
circuit between the voltage source and the
switch), voltage isn’t reaching the brake light
Braking system 9•13
9
12.5j Place the front shoe in position,
insert the pin through the backing plate
and the shoe . . .12.5k . . . and refit the hold-down spring
and washers12.5i Lubricate the six friction points
(two arrowed) on the backing plate with
high-temperature brake grease
3261 Jaguar XJ6 12.5l Hook the lower return spring into its
hole in the front shoe . . .
12.5m . . . hook the other end of the
lower spring into the rear shoe . . .12.5n . . . stretch the spring over the top of
the handbrake lever box . . .
12.5o . . . place the rear shoe in position,
insert the pin through the backing plate
and the shoe and refit the rear washers
and hold-down spring12.5p Hook the upper return spring into
the front shoe . . .
12.5q . . . and into the rear shoe12.5r Pull the shoes apart and refit the
adjuster mechanism
bulbs (open-circuit between the switch and
the bulbs), or the switch is defective.
5To remove the switch, reach up under the
dash and unplug the two electrical connectors
- one for the brake lights and one for the
cruise control system. Locate the two pairs of
leads coming down the pedal box and trace
them to their connectors on or near the
steering column.
6Remove the three switch-plate retaining
bolts and remove the switch assembly (see
illustrations). Inspect the switch-plate rubber
gasket for cracks or deterioration and renew it
if it’s damaged or worn.
7Place the switch assembly on a workbench
and connect an ohmmeter to the brake lightswitch terminals. With the switch plunger in its
normal, extended position (brake pedal not
applied), there should be no continuity (infinite
resistance) (see illustration); when the
plunger is depressed (brake pedal applied),
there should be continuity (zero resistance)
(see illustration). If the switch doesn’t
perform as described, renew it. If the switch
works in an opposite fashion, i.e. continuity
when the plunger is free, no continuity when
the plunger is depressed, you’ve tested the
cruise control switch! Switch the ohmmeter
leads to the other connector and recheck.
8To remove the switch from the plate,
remove the two small nuts on the back of the
plate (see illustration).9Refit the switch assembly and the switch
plate bolts but don’t tighten the bolts yet.
10Plug in the brake light and cruise control
connectors.
11The holes in the switch plate are slotted
for adjustment. While an assistant presses the
brake pedal, verify that the brake lights come
on; with the pedal released, make sure the
brake lights are off. If the lights don’t come on
when the pedal is depressed, or stay on when
the pedal is released, adjust the switch by
moving the plate until proper operation is
achieved. Tighten the switch-plate bolts.
12After tightening the switch-plate bolts,
check the switch again to make sure it
performs properly.
9•14 Braking system
13.6a To remove the brake light switch,
remove the three mounting plate screws
(arrowed) . . .13.6b . . . and carefully pry the switch plate
away from the pedal box - be careful not to
damage the gasket13.7a To check the brake light switch,
connect an ohmmeter to the switch
terminals; with the switch plunger
released, there should be no continuity
(infinite resistance)
13.7b With the switch plunger depressed,
there should be continuity
(zero resistance)13.8 If you’re replacing the switch, remove
these two nuts (arrowed) and transfer the
retaining plate to the new switch
3261 Jaguar XJ6
3Remove two bumper retaining bolts located
on the bottom side of the bumper (see
illustration). Pull the bumper assembly out
and away from the vehicle to remove it.
4Refitting is the reverse of removal.
15 Front wing-
removal and refitting
3
1Loosen the front wheel nuts. Raise the
vehicle, support it securely on axle stands and
remove the front wheel.
2Remove the front bumper assembly (see
Section 14).
3Remove the front spoiler (see Section 13).4Detach the inner wing splash shield (see
illustration).
5On 1988 and 1989 models, remove the
coolant overflow reservoir located behind the
splash shield (see Chapter 3).
6On models with round headlights, remove
the headlight bezel. On models with
composite headlights (1992 Vanden Plas, all
1993 and later models), remove the headlight
(see Chapter 12).
7Remove the wing mounting bolts and nuts
(see illustrations).
8Detach the wing. It’s a good idea to have an
assistant support the wing while it’s being
moved away from the vehicle to prevent
damage to the surrounding body panels.
9Refitting is the reverse of removal.
16 Boot lid- removal,
refitting and adjustment
2
Note:The boot lid is heavy and somewhat
awkward to remove and refit - at least two
people should perform this procedure.
Removal and refitting
1Open the boot lid and cover the edges of
the boot compartment with pads or cloths to
protect the painted surfaces when the lid is
removed.
2Disconnect any cables or wire harness
connectors attached to the boot lid that would
interfere with removal.
3Make alignment marks around the hinge
mounting bolts with a marking pen.
4While an assistant supports the boot lid,
remove the lid-to-hinge bolts on both sides
and lift it off(see illustration).
5Refitting is the reverse of removal. Note:
When refitting the boot lid, align the lid-to-
hinge bolts with the marks made during
removal.
Adjustment
6Fore-and-aft and side-to-side adjustment
of the boot lid is done by moving the bonnet in
relation to the hinge plate after loosening the
bolts or nuts.
7Scribe a line around the entire hinge plate
as described earlier in this section so you can
judge the amount of movement.
11•6 Bodywork and fittings
14.3 Remove the two retaining bolts from
the bottom of the bumper, then remove the
bumper from the vehicle15.4 Remove the bolts (arrowed) securing
the inner wing splash shield15.7a Detach the wing retaining bolts
(arrowed) at the front of the wing
15.7c Working in the wheel opening,
remove the wing-to-rocker panel bolt
(arrowed)
15.7d Remove the wing-to-door pillar bolt
(arrow; lower bolt not visible)15.7e Detach the bolts along the
top of the wing
3261 Jaguar XJ6
15.7b Remove the wing-to-radiator
support bolt (arrowed)
16.4 With the help of an assistant to hold
the boot lid, remove the retaining bolts and
lift off the boot lid
selector towards the rear of the vehicle. Pull
up on the rear half of the radio trim bezel while
gently detaching the clips securing the front,
then remove the bezel from the vehicle.
6Remove the radio and heater control
assembly (see Chapter 12).
7Remove the dashboard centre trim panel
(see Section 26), then remove the centre air
conditioning duct from the vehicle (see
illustration).
8Remove the retaining screws located in the
air conditioning duct opening (see illustration).
9Remove the plastic screws securing the
lower front section of the console (see
illustration).
10Unplug any electrical connectors that will
interfere with the removal of the console.
11Pull the console towards the rear of the
vehicle, then lift the console up over the shift
lever and remove it from the vehicle.
12Refitting is the reverse of removal.
Overhead console
13Remove the plastic screw securing the
overhead console, then carefully pull the
console out of the headliner (see illustration).
14Disconnect the electrical connectors from
the lights.
15Refitting is the reverse of removal.
25 Instrument cluster housing-
removal and refitting
2
Warning: Later models are
equipped with airbags. To
prevent the accidental deploy-
ment of the airbag, which could
cause personal injury or damage to the
airbag system, DO NOT work in the vicinity
of the steering column or instrument panel.
The manufacturer recommends that, on
airbag equipped models, the following
procedure should be left to a dealer service
department or other repair workshop
because of the special tools and techniques
required to disable the airbag system.
1Disconnect the negative battery cable. Caution: If the stereo in your vehicle is
equipped with an anti-theft system, make
sure you have the correct activation code
before disconnecting the battery.
2Remove the drivers side knee bolster (see
Section 26).
3Place the steering wheel in the full rearward
position. If the vehicle is equipped with a tilt
column, place the steering wheel in the lowest
position.
4Remove the instrument cluster housing
screws (see illustration).
5Pull the instrument cluster housing outward
to access the electrical connections on the
backside (see illustration).
6Disconnect all electrical connections from
the backside of the cluster housing and
remove the housing from the vehicle.
7Refitting is the reverse of removal.
11•12 Bodywork and fittings
24.3b Pull the ash tray towards the rear of
the vehicle to remove it - don’t pull it
straight up24.4 Working through the ash tray opening,
remove the radio trim bezel wingnuts
(arrowed) located under the trim bezel24.7 After removing the centre trim panel,
detach the air conditioning duct
24.8 Remove the retaining screws in the
air conditioning duct opening24.9 Remove the plastic screws (arrowed)
from each side of the console24.13 Remove the plastic screw, then pull
the overhead console down and unplug
the electrical connectors
3261 Jaguar XJ6
25.4 Working in the knee bolster opening,
remove two retaining screws from each
end of the instrument cluster housing25.5 Pull outward on the instrument
cluster housing and unplug the electrical
connectors from the backside
personal injury or damage to the airbag
system, DO NOT work in the vicinity of the
steering column or instrument panel. The
manufacturer recommends that, on airbag
equipped models, the following procedure
should be left to a dealer service
department or other repair workshop
because of the special tools and techniques
required to disable the airbag system.
1Remove the steering wheel (Chapter 10)
2Remove the knob from the rheostat
(dimmer) for the instrument panel lights (see
illustration).
3Remove the lower steering column cover
screws (see illustration), then detach the
lower cover.
4Working through the lower cover opening,
remove the four screws securing the upper
half of the cover, then pull the cover forward
and out to remove it (see illustration).
5Refitting is the reverse of removal.
28 Cowl cover-
removal and refitting
2
1Remove the windscreen wiper arms (see
Chapter 12).2Remove the retaining screws located along
the top of the cowl cover (see illustration).
3Lift the cowl cover up slightly, then detach
the electrical connectors and the spray nozzle
hoses from the backside of the cowl cover.
4Detach the cowl cover from the vehicle.
5Refitting is the reverse of removal.
29 Seats- removal and refitting
2
Front seat
1Position the seat all the way forward or all
the way to the rear to access the front seat
retaining bolts.
2Detach any bolt trim covers and remove the
retaining bolts (see illustration).
3Tilt the seat upward to access the
underneath, then unplug any electrical
connectors and lift the seat from the vehicle.
4Refitting is the reverse of removal.
Rear seat
5Remove retaining screws at the lower edge
of the seat cushion (see illustration). Then lift
up on the front edge and remove the cushion
from the vehicle.
6Detach the retaining bolts at the lower edge
of the seat back.
7Lift up on the lower edge of the seat back to
release the clips securing the top. Then
remove it from the vehicle.
8Refitting is the reverse of removal.
11•14 Bodywork and fittings
27.4 Remove the four screws securing the
upper half of the steering column cover
28.2 Remove the screws (arrowed)
located along the top of the cowl cover29.2 Use a Torx bit to remove the front
seat retaining bolts (arrowed)
3261 Jaguar XJ6 27.2 Pull off the knob from the instrument panel light rheostat
27.3 Remove the lower steering column cover screws
29.5 Detach the screws (arrowed) along
the lower edge of the seat cove