1997 JAGUAR XJ6 turn signal

28Check the signal voltage from the
potentiometer. Carefully backprobe the
electrical connector on the signal voltage
wire (-) with the ignition key ON (engine not
running) (see illustration). There should be
approximately 0.5 volts.
29Next, rotate the throttle lever manually and
confirm that the reference voltage increases to
approximately 4.8 volts (see illustration).
30If the voltage does not increase, renew
the throttle potentiometer with a new part.
Renewal
31Remove the throttle body from the intake
manifold (see Chapter 4).
32Remove the two mounting bolts and
separate the throttle potentiometer from the
throttle body. Note:The throttle potentiometer
is difficult to reach and adjustment requires
that the home mechanic tighten the bolts after
the final adjustment using a mirror. Be sure to
mark the mounting position of the old throttle
potentiometer before refitting the new part.
33Refitting is the reverse of removal.
Adjustment
34Refit the throttle body with the throttle
potentiometer mounting bolts just looseenough to move the potentiometer. Be sure
the bolts are tight and the potentiometer does
not rotate easily.
35Backprobe the signal wire and the ground
wire (see Step 28) and with the throttle closed
(idle position), rotate the potentiometer until
the voltmeter reads between 0.2 and 0.5 volts.
Note:The throttle potentiometer is difficult to
reach. Be sure to rotate the potentiometer
slowly and do not interfere with the voltmeter
and the electrical connectors to the gauge.
36Rotate the throttle lever and confirm that
the voltage increases to around 4.8 volts.
If the voltage range is correct, the throttle
potentiometer is installed correctly.
37Tighten the throttle potentiometer bolts. If
necessary, use a small mirror to locate the
bolts.
Mass airflow (MAF) sensor
General Information
38The mass airflow sensor (MAF) is located
on the air intake duct. This sensor uses a hot
wire sensing element to measure the amount
of air entering the engine. The air passing over
the hot wire causes it to cool. Consequently,this change in temperature can be converted
into an analogue voltage signal to the ECU
which in turn calculates the required fuel
injector pulse width.
Check
39Check for power to the MAF sensor.
Backprobe the MAF sensor electrical plug.
Working on the harness side with the ignition
ON (engine not running), check for battery
voltage on terminal number 5 (see illustration).
40Remove the pin and backprobe the MAF
sensor electrical connector terminal number 3
with the voltmeter (see illustration). The
voltage should be less than 1.0 volt with the
ignition switch ON (engine not running). Raise
the engine rpm. The signal voltage from the
MAF sensor should increase to about 2.0 volts.
It is impossible to simulate load conditions in
the driveway but it is necessary to observe the
voltmeter for a fluctuation in voltage as the
engine speed is raised. The vehicle will not be
under load conditions but MAF sensor voltage
should vary slightly.
41If the voltage readings are correct, check
the wiring harness for open circuits or a
damaged harness (see Chapter 12).
6•6 Emissions and engine control systems
4.29 . . . then check the SIGNAL voltage
with the throttle wide open. It should be
between 4.5 and 5.0 volts4.39 Check for battery voltage to the MAF
sensor on terminal number 54.40 With the engine idling, raise the engine
rpm and observe the voltage changes on
terminal number 3
3261 Jaguar XJ6 4.27 Backprobe the throttle potentiometer electrical connector
with a pin and with the ignition key ON (engine not running) there
should be 5.0 volts REFERENCE available
4.28 First check the throttle potentiometer SIGNAL voltage with the
throttle closed (idle). It should be 0.2 to 0.5 volts . . .

42Also, check the reference voltage to the
MAF sensor from the computer. Backprobe
terminal number 6 and make sure that
approximately 5 volts is present.
Renewal
43Disconnect the electrical connector from
the MAF sensor.
44Remove the air cleaner assembly (see
Chapter 4).
45Remove the four bolts and separate the
MAF sensor from the air intake duct.
46Refitting is the reverse of removal.
Intake air temperature
(IAT) sensor
General description
47The intake air temperature sensor is
located inside the air intake duct. This sensor
acts as a resistor which changes value
according to the temperature of the air entering
the engine. Low temperatures produce a high
resistance value (for example, at 68° F the
value is 2.0 to 2.6 k-ohms) while high
temperatures produce low resistance values (at
176° F the resistance is 260 to 330 ohms. The
ECU supplies around 5 volts (reference
voltage) to the air temperature sensor.
The voltage will change according to the
temperature of the incoming air. The voltage
will be high when the air temperature is cold
and low when the air temperature is warm. Any
problems with the air temperature sensor
will usually set a code 8 (1988 and 1989) or
code 16 (1990 to 1994).
Check
48To check the air temperature sensor,
disconnect the two prong electrical connector
and turn the ignition key ON but do not start
the engine.
49Measure the voltage (reference voltage),
which should be approximately 5 volts.
50If the voltage signal is not correct, havethe ECU diagnosed by a dealer service
department or other repair workshop.
51Measure the resistance across the air
temperature sensor terminals (see illustration).
The resistance should be HIGH when the air
temperature is LOW. Next, start the engine and
let it idle. Wait awhile and let the engine reach
operating temperature. Turn the ignition OFF,
disconnect the air temperature sensor and
measure the resistance across the terminals.
The resistance should be LOW when the air
temperature is HIGH. If the sensor does not
exhibit this change in resistance, renew it with a
new part.
EGR gas temperature sensor
(1991 to 1994 models)
General description
52The EGR gas temperature sensor is
mounted in the exhaust gas transfer pipe. This
sensor detects the temperature of the exhaust
moving through the EGR valve. The information
is sent to the ECU so the EGR on/off time is
regulated precisely and efficiently.
Check
53Disconnect the harness connector for the
EGR gas temperature sensor and measure
the resistance of the sensor at the various
temperatures. Refer to the Specifications
listed in this Chapter for a list of the
temperatures and the resistance values.
Removal and refitting
54Disconnect the harness connector for the
EGR gas temperature sensor and using an
open-end spanner, remove the sensor from
the EGR adapter under the intake manifold.
55Refitting is the reverse of removal.
Speed sensor
General description
56The speed sensor is mounted on thedifferential housing and monitors vehicle
speed by sensing the rotational speed of the
rear axle. A problem with this sensor or circuit
will set a code 68 and may also be the cause
of an inoperative speedometer. If the
speedometer doesn’t work, the problem lies
in the speed sensor, the instrument cluster,
the ECU or the wiring in between. For further
diagnosis, take the vehicle to a dealer service
department or other suitably-equipped and
qualified repair workshop.
Crankshaft position sensor
57The crankshaft position sensor is located
in the front timing cover near the crankshaft
pulley (see illustration). The crankshaft
position sensor relays a signal to the ECU to
indicate the exact position (angle) of the
crankshaft.
Check
58The crankshaft sensor cannot be
diagnosed without the proper tools. The
Jaguar dealer uses a diagnostic scope/
computer called the JDS. Have the crankshaft
sensor diagnosed by the dealer service
department or other qualified repair workshop.
Renewal
59To renew the sensor, disconnect the
electrical connector and remove the bolt from
the crankshaft position sensor. Refitting is the
reverse of removal.
60To renew the crankshaft sensor gear,
remove the front pulley (refer to Chapter 2A).
61Be sure there is a small gap between the
crankshaft sensor and the teeth on the gear. It
should be between 0.46 to 1.07 mm (0.018 to
0.042 inch).
62Refitting is the reverse of removal. Tighten
the crankshaft sensor bolt to the torque listed
in this Chapter’s Specifications.
Emissions and engine control systems 6•7
6
3261 Jaguar XJ6 4.51 The air intake temperature sensor resistance will DECREASE
when the temperature of the air INCREASES
4.57 Location of the crankshaft position sensor

Test the brakes at various speeds with both
light and heavy pedal pressure. The vehicle
should stop evenly without pulling to one side
or the other. Avoid locking the brakes,
because this slides the tyres and diminishes
braking efficiency and control of the vehicle.
Tyres, vehicle load and wheel alignment are
factors which also affect braking performance.
2 Anti-lock Brake system
(ABS)- general information
The Anti-lock Brake System is designed to
maintain vehicle steerability, directional stability
and optimum deceleration under severe
braking conditions on most road surfaces. It
does so by monitoring the rotational speed of
each wheel and controlling the brake line
pressure to each wheel during braking. This
prevents the wheels from locking up.
The ABS system has three main units - the
wheel speed sensors, the electronic control unit
and the modulator (hydraulic control unit). The
sensors - one at each wheel - send a variable
voltage signal to the electronic control unit,
which monitors these signals, compares them
to its program and determines whether a wheel
is about to lock up. When a wheel is about to
lock up, the control unit signals the hydraulic
unit to reduce hydraulic pressure (or not
increase it further) at that wheel’s brake caliper.
Pressure modulation is handled by three
electrically-operated solenoid valves - one for
each front wheel and one for the rear wheels -
inside the modulator.
If a problem develops within the system, an
“ABS” warning light will glow on the dashboard.
Sometimes, a visual inspection of the ABS
system can help you locate the problem.
Carefully inspect the ABS wiring harness. Pay
particularly close attention to the harness and
connections near each wheel. Look for signs of
chafing and other damage caused by
incorrectly routed wires. If a wheel sensor
harness is damaged, the sensor should be
replaced (the harness and sensor are integral).
Warning: Do NOT try to repair an
ABS wiring harness. The ABS
system is sensitive to even thesmallest changes in resistance. Repairing
the harness could alter resistance values
and cause the system to malfunction. If the
ABS wiring harness is damaged in any way,
it must be replaced.
Caution: Make sure the ignition is turned
off before unplugging or reattaching any
electrical connections.
Diagnosis and repair
If a dashboard warning light comes on and
stays on while the vehicle is in operation, the
ABS system requires attention. Although
special electronic ABS diagnostic testing tools
are necessary to properly diagnose the system,
you can perform a few preliminary checks
before taking the vehicle to a dealer service
department or other qualified repair workshop.
a) Check the brake fluid level in the master
cylinder reservoir.
b) Verify that all ABS system electrical
connectors in the engine compartment
are plugged in.
c) Check the fuses.
d) Follow the wiring harness to each front
wheel and to the differential sensor and
verify that all connections are secure and
that the wiring is undamaged.
If the above preliminary checks do not
rectify the problem, the vehicle should be
diagnosed by a dealer service department.
Due to the complex nature of this system, all
actual repair work must be done by a dealer
service department or other qualified repair
workshop.
3 Disc brake pads- renewal
2
Warning: Disc brake pads must
be replaced on both front wheels
or both rear wheels at the same
time - never renew the pads on
only one wheel. Also, the dust created by
the brake system may contain asbestos,
which is harmful to your health. Never blow
it out with compressed air and don’t inhale
any of it. An approved filtering mask should
be worn when working on the brakes. Do
not, under any circumstances, use
petroleum-based solvents to clean brake
parts. Use brake system cleaner only!
Note:The following procedure applies to both
the front and rear brake pads.
1Remove the cap from the brake fluid
reservoir and siphon off about two-thirds of
the fluid from the reservoir. Failing to do this
could result in fluid overflowing when the
caliper pistons are pressed into their bores.
2Loosen the wheel nuts, raise the front of the
vehicle and support it securely on axle stands.
3Remove the front wheels. Work on one
brake assembly at a time, using the
assembled brake for reference if necessary.
4Inspect the brake disc (see Section 5).
5Follow the accompanying photos,
beginning with illustration 3.5a, for the pad
removal procedure. Be sure to stay in order
and read the caption under each illustration.
9•2 Braking system
3.5a Before starting, wash down the
caliper and disc with brake cleaner
3.5b Attach a hose to the bleed screw,
open the bleed screw slightly and depress
the piston into the caliper. Tighten the
bleed screw when the piston bottoms
3.5c Remove the caliper mounting bolts
(upper bolt arrowed); use another spanner
to hold the flats of the caliper guide pins
while you back out the caliper bolts3.5d Remove the caliper . . .3.5e . . . and suspend it out of the way
with a piece of wire
3261 Jaguar XJ6

actuators, a control unit and associated
wiring. Diagnosis can usually be limited to
simple checks of the wiring connections and
actuators for minor faults which can be easily
repaired. Since this system uses an electronic
control unit, in-depth diagnosis should be left
to a dealership service department.
Central locking systems are operated by bi-
directional solenoids located in the doors. The
lock switches have two operating positions;
Lock and Unlock. When activated, the switch
sends a signal to the door lock control unit to
lock or unlock the doors. Depending on which
way the switch is activated, the control unit
reverses polarity to the solenoids, allowing the
two sides of the circuit to be used alternately
as the feed (positive) and earth side.
Some vehicles may have an anti-theft
system incorporated into the locks. If you are
unable to locate the trouble using the following
general paragraphs, consult a dealer service
department or other properly equipped repair
facility.
1Always check the circuit protection first.
Some vehicles use a combination of circuit
breakers and fuses.
2Operate the door lock switches in both
directions (Lock and Unlock) with the engine off.
Listen for the click of the solenoids operating.
3Test the switches for continuity. Renew the
switch if there’s not continuity in both switch
positions.
4Check the wiring between the switches,
control unit and solenoids for continuity.
Repair the wiring if there’s no continuity.
5Check for a bad earth at the switches or the
control unit.
6If all but one lock solenoid operates,
remove the trim panel from the affected door
(see Chapter 11) and check for voltage at the
solenoid while the lock switch is operated
(see illustration). One of the wires should
have voltage in the Lock position; the other
should have voltage in the Unlock position.
7If the inoperative solenoid is receiving
voltage, renew the solenoid.
8If the inoperative solenoid isn’t receiving
voltage, check for an open or short in the wire
between the lock solenoid and the control
unit. Note:It’s common for wires to break in
the portion of the harness between the body
and door (opening and closing the door
fatigues and eventually breaks the wires).26 Electric mirrors-
description and check
2
1Most electric mirrors use two motors to
move the glass; one for up and down
adjustments and one for left-right adjustments.
2The control switch has a selector portion
which sends voltage to the left or right side
mirror. With the ignition ON but the engine
OFF, roll down the windows and operate the
mirror control switch through all functions
(left-right and up-down) for both the left and
right side mirrors.
3Listen carefully for the sound of the electric
motors running in the mirrors.
4If the motors can be heard but the mirror
glass doesn’t move, there’s probably a
problem with the drive mechanism inside the
mirror. Remove and dismantle the mirror to
locate the problem.
5If the mirrors don’t operate and no sound
comes from the mirrors, check the fuse (see
Chapter 1).
6If the fuse is OK, remove the mirror control
switch from its mounting without
disconnecting the wires attached to it. Turn
the ignition ON and check for voltage at the
switch. There should be voltage at one
terminal. If there’s no voltage at the switch,
check for an open or short in the circuit
between the fuse panel and the switch.
7If there’s voltage at the switch, disconnect
it. Check the switch for continuity in all its
operating positions. If the switch does not
have continuity, renew it.
8Re-connect the switch. Locate the wire
going from the switch to earth. Leaving the
switch connected, connect a jumper wire
between this wire and earth. If the mirror
works normally with this wire in place, repair
the faulty earth connection.
9If the mirror still doesn’t work, remove the
mirror and check the wires at the mirror for
voltage. Check with ignition ON and the mirror
selector switch on the appropriate side.
Operate the mirror switch in all its positions.
There should be voltage at one of the switch-
to-mirror wires in each switch position (except
the neutral “off” position).
10If there’s not voltage in each switch
position, check the circuit between the mirror
and control switch for opens and shorts.
11If there’s voltage, remove the mirror and
test it off the vehicle with jumper wires. Renew
the mirror if it fails this test.
27 Electric sunroof-
description and check
2
1The electric sunroof is powered by a single
motor in the roof behind the overhead console.
The power circuit is protected by a fuse.
2The control switches (tilt and slide) send an
earth signal to the sunroof motor when theswitches are pressed. Power is supplied to
the motor from the relay. With the ignition ON
but the engine OFF, operate the sunroof
control switch through the tilt and slide
functions.
3Listen carefully for the sound of the sunroof
motor running in the roof.
4If the motors can be heard but the sunroof
glass doesn’t move, there’s probably a
problem with the drive mechanism or drive
cables.
5If the sunroof does not operate and no
sound comes from the motor, check the fuse
(see Chapter 1).
6If the fuse is OK, remove the control
switches (see Chapter 11). Disconnect the
wires attached to it. Turn the ignition ON and
check for voltage at the switch. If there’s no
voltage at the switch, check for power and
earth at the motor. If power and earth exist at
the motor and there’s still no voltage at the
switch renew the motor. If there’s no voltage
at the motor, check the relay or an open or
short in the wiring between the relay and the
motor.
7If there’s voltage at the switch, disconnect
it. Check the switch for continuity in all its
operating positions. If the switch does not
have continuity, renew it.
8If the switch has continuity re-connect the
switch. Locate the wire going from the switch
to earth. Leaving the switch connected,
connect a jumper wire between this wire and
earth. If the motor works normally with this
wire in place, repair the faulty earth
connection.
9The sunroof can be closed manually by
inserting the T-handle spanner which is
located inside the overhead console. Insert
the spanner into the motor drive shaft and
rotate the shaft clockwise (see illustration).
28 Airbag system-
general information
Warning: Failure to follow these
precautions could result in
accidental deployment of the
airbag and personal injury.
12•14 Body electrical system
25.6 Check for voltage at the lock
solenoid while the lock switch is operated27.9 To close the sunroof manually, insert
the T-handle spanner in the motor shaft
and rotate it clockwise
3261 Jaguar XJ6

Wiring diagrams 12•23
12
3261 Jaguar XJ6
Typical hazard/turn signal and stop light system

3261 Jaguar XJ6
Use of EnglishREF•3
As the main part of this book has been written in the US, it uses the appropriate US component names, phrases, and spelling. Some of these
differ from those used in the UK. Normally, these cause no difficulty, but to make sure, a glossary is printed below. When ordering spare parts,
remember the parts list may use some of these words:
AMERICAN ENGLISH
Aluminum Aluminium
Antenna Aerial
Authorized Authorised
Auto parts stores Motor factors
Axleshaft Halfshaft
Back-up Reverse
Barrel Choke/venturi
Block Chock
Box-end wrench Ring spanner
Bushing Bush
Carburetor Carburettor
Center Centre
Coast Freewheel
Color Colour
Convertible Drop head coupe
Cotter pin Split pin
Counterclockwise Anti-clockwise
Countershaft (of gearbox) Layshaft
Dashboard Facia
Denatured alcohol Methylated spirit
Dome lamp Interior light
Driveaxle Driveshaft
Driveshaft Propeller shaft
Fender Wing/mudguard
Firewall Bulkhead
Flashlight Torch
Float bowl Float chamber
Floor jack Trolley jack
Freeway, turnpike etc Motorway
Freeze plug Core plug
Frozen Seized
Gas tank Petrol tank
Gasoline (gas) Petrol
Gearshift Gearchange
Generator (DC) Dynamo
Ground (electrical) Earth
Header Exhaust manifold
Heat riser Hot spot
High Top gear
Hood (engine cover) Bonnet
Installation Refitting
Intake Inlet
Jackstands Axle stands
Jumper cable Jump lead
Keeper Collet
Kerosene Paraffin
Knock pin Roll pin
Lash Clearance
Lash Free-play
Latch Catch
Latches Locks
License plate Number plate
Light Lamp
Lock (for valve spring retainer) Split cotter (for valve spring cap)
Lopes Hunts
Lug nut/bolt Wheel nut/bolt
Metal chips or debris Swarf
Misses Misfires
AMERICAN ENGLISH
Muffler Silencer
Odor Odour
Oil pan Sump
Open flame Naked flame
Panel wagon/van Van
Parking brake Handbrake
Parking light Sidelight
Pinging Pinking
Piston pin or wrist pin Gudgeon pin
Piston pin or wrist pin Small end, little end
Pitman arm Drop arm
Power brake booster Servo unit
Primary shoe (of brake) Leading shoe (of brake)
Prussian blue Engineer’s blue
Pry Prise (force apart)
Prybar Lever
Prying Levering
Quarter window Quarterlight
Recap Retread
Release cylinder Slave cylinder
Repair shop Garage
Replacement Renewal
Ring gear (of differential) Crownwheel
Rocker panel (beneath doors) Sill panel (beneath doors)
Rod bearing Big-end bearing
Rotor/disk Disc (brake)
Secondary shoe (of brake) Trailing shoe (of brake)
Sedan Saloon
Setscrew, Allen screw Grub screw
Shock absorber, shock Damper
Snap-ring Circlip
Soft top Hood
Spacer Distance piece
Spare tire Spare wheel
Spark plug wires HT leads
Spindle arm Steering arm
Stabilizer or sway bar Anti-roll bar
Station wagon Estate car
Stumbles Hesitates
Tang or lock Tab washer
Throw-out bearing Thrust bearing
Tie-rod or connecting rod (of steering) Trackrod
Tire Tyre
Transmission Gearbox
Troubleshooting Fault finding/diagnosis
Trunk Boot (luggage compartment)
Turn signal Indicator
TV (throttle valve) cable Kickdown cable
Unpublicized Unpublicised
Valve cover Rocker cover
Valve lifter Tappet
Valve lifter or tappet Cam follower or tappet
Vapor Vapour
Vise Vice
Wheel cover Roadwheel trim
Whole drive line Transmission
Windshield Windscreen
Wrench Spanner