1998 JAGUAR X308 tire pressure

Install brake pads
i
nto caliper.
Slo

wly retract caliper pi
stons into caliper.
1. Install pads.
2. Position anti-rattle spring.
3. Install pins.
4. Install 'R' clips.
4. Repeat above procedure to install opposite side brake pads.
5. Fit wheels.
For additional information, refer to: Wheel and Tire
(20
4-04
Wheels and Tires, Remo val and Installation).
6. Remove stands and lower vehicle.
For additional information, refer to: Using the Workshop Jack

(10
0-02 Jacking and Lifting, General Procedures).

7. CAUTI
ON: Remove brake flui
d spillage immediately from
paint work, with clean water.
Check brake fluid level.
Check brak
e fluid level is
at the maximum mark.
Re
move cloth.
Fi

t cap.
8.
R
emove paint work protection
covers, and close engine
compartment.
9. Start the engine and repeatedly press the brake pedal until
brake pressure is evident.

Install brake pads.
1
. Install pads.
2. Position anti-rattle spring.
3. Install pins - make sure pin collets are fully engaged
into caliper.
4. Repeat above procedure to install opposite side brake pads.
5. Fit wheels.
For additional information, refer to: Wheel and Tire
(20
4-04
Wheels and Tires, Remo val and Installation).
6. Remove stands an d lower vehicle.
For additional information, refer to: Using the Workshop Jack

(10
0-02 Jacking and Lifting, General Procedures).

7. CAUTI
ON: Remove brake flui
d spillage immediately from
paint work, with clean water.
Check brake fluid level.
Check brak
e fluid level is
at the maximum mark.
Re
move cloth.
Fi

t cap.
8.
R
emove paint work protection
covers, and close engine
compartment.
9. Start the engine and repeatedly press the brake pedal until
brake pressure is evident.

It is a reciprocating two
-circuit pu
mp in which one brake circuit is as signed to each pump circuit.
It supplies th
e fluid pressure and vo
lume to supply the brake circuits under ABS and Traction control.
The pump is driven by an electri
c motor, with the pump
housing incorporating two lo w pressure accumulators and
damping chambers for each brake circuit.
The ac cu
mulator stores the pressure and smooths out the output pu
lses from the pump.
ABS Warning Lamp
The sys
tem will be set in a fail-safe mode if a problem is de
tected; a warning lamp on the instrument panel will notify the
driver there is a problem.
Anti-Lock Braking Sy
stem (ABS)
The AB
S components are combined with
an hydraulic booster and a tandem master cylinder to provide a two circuit braking
system. The system comprises, four wheel speed sensor s, a brake control modulator and an ABS warning lamp.
Should a wheel start to lock-up during braking a signal tr ansmitted from the wheel speed sensor to the brake control
modulator will start the hydraulic pump. The brake control modula tor will close the input valve of the line connected to the
locked-wheel to stop any increase in fluid pressure to the br ake caliper. If this fails to prevent the wheel locking, the
pressure in the caliper will be decreased by opening the return valve until th e wheel starts accelerating again. The fluid
pressure from the return va lve is directed into the low pressure accumulator, housed in the pump.
From the low pressure accumulator, fl uid is pumped through the damping cham ber to the brake master cylinder. The
pressure to the brake caliper will then be increased in small steps to maintain maximum adhesion between the tire and road
surface. This is achieved by closing the return valve, and opening the input valve and using the hydraulic pump to increase
the pressure.
Although the system senses all four wheels independently, the rear wheels are regulated as a pair. If a sensor on a rear
wheel detects a wheel decelerating rapidly, then the fluid pressure to both wheels is reduced. The fluid pressure is then
dictated by the wheel having the lowe st adhesion with the road surface.
The ABS system will be set in a fail-safe mode if a problem is detected; a warn ing lamp on the instrument panel will notify
the driver there is a problem. The brake system will still operate conventionally and with the same standard of performance
as a vehicle not equipped with ABS.
Automa tic Stability Control (ASC)

Th
e ASC utilizes the ABS sensing arrangement to provide the maximum traction force to propel the vehicle.
The ASC is switched on when the engine is started. The system can be switched off by pressing the 'ASC OFF' (the switched
is marked 'TRAC OFF' on vehicles fitted with traction control). The switch, which is situated in the center console switchpack,
lights up to warn that the system is sw itched off. An 'ASC' amber warning light flashes on the instrument panel when the
system detects a spinning wheel.
The ASC system uses engine intervention to reduce the torque delivered to the drive wheels to prevent them spinning.
Engine torque is re duced in three ways:
The
throttle is moved towards the closed position.
The ignition is retarded. F
u
el is cut-off at the cylinder injectors.
Wheel spin is detected by the wheel sp eed sensors and communicated to the AB S/TCCM. The ABS/TCCM uses information
from the controller area network (CAN) to calculate the torque that the engine should produce to stop the wheel spinning.
Torque reductions are then requested from the engine control module (ECM ) through the CAN. The throttle is then
positioned to provide the target torque, which has been calculated to prevent wheel spin. During the transient phase of
torque reduction the fuel is cut-off and th e ignition retarded Both the fuel cut-off an d ignition retard will be restored to
normal when the throttle is set to its new position.
The ASC uses a brake control modulator with six solenoid va lves: three normally open inlet valves and three normally

Steering System - General Inform
ation - Steering System
D
iagnosis and Testing
I

nspection and Verification
1.
1. Verify t
he customer concern by driving the vehicle.
2. 2. Visually inspect for obvious signs of mechanical or electrical damage.
Mec
hanical Inspection Chart
Electrical Inspection Chart
Mechanical Checks
Incorrect
tire pressure, loose whee
l nuts, incorrect wheel alignment
Loose ti
e-rods
Loose dam

per and spring assemblies or ball joint
Loose s

teering column shaft universal joints
Loose pinc

h bolts on steering column shaft
Loose steeri

ng gear assembly
Check f

or external damage to the steering gear.
- Damaged tie-rods
-
CAUTION: If a steering gear assemb ly is returned under warranty with leaking seals, but there is also
damage to the steering gear boot/boots the steering gear warranty will be invalid. This is due to the steering
gear seals being damaged due to fore ign materials entering the steering gear boot and damaging the steering
gear seals thereafter.
Damaged steering gear boot
Damaged accessory driv
e belt
Bin

ding or misaligned steering co
lumn, pump or steering gear
Incorrect fluid
level
Hose leaks o

r line restrictions
Hose fou

ling bodywork
El

ectrical Checks/Tests
Make sure all

connectors are in plac
e (steering gear Servotronic solenoid and steering control module (SCM) - if
applicable)
Make su
re all the fuses are in place and not blown
D

ISCONNECT the steering gear transducer
and the steering should become heavy
TEST e
lectrical values:
- Power Supply to the SCM = 12 Volts
- Steering gear transducer resist ance 7.0 to 7.5 Ohms is normal
(
limits: less than 5 Ohms and greater than 9 Ohms would

be declared unacceptable)

- Steeri
ng gear transducer voltage = 6 Volts
- Steering gear transducer cu rrent = 840 mA at 0 mph reducing to 0 mA at maximum speed

Vehicl
e wanders from side to

side on the road, when the vehicle is driven straight ahead and the steering wheel is held in a firm position
Incorrect ti re
pressure or
tire size.
CHECK and ADJ
UST the tire pressure. For
additional information,
REFER to Section 204
-0 4
Wheels and Tires
. IN
ST
ALL a new tire as necessary. For
additional information,
REFER to Section 204
-0 4
Wheels and Tires
.
Vehi
cl
e is unevenly or
excessively loaded.
A D
JUST the load evenly.
Loose/worn ti
e-
rods.
INST
ALL a ne
w tie-rod
end. For additional
information,
REFER to Section 211
-0 3
Steering Linkage
.
Steeri
ng gear bolts loose
o
r damaged.
TIGHTE
N or INSTALL
new bolts.
Loose or worn suspensi
on
ball jo
int(s).
INST
ALL a ne
w suspension ball joint
assembly. For additional information,
REFER to Section 204
-01 Fron
t Suspension
.
Steeri
ng column uni
versal
joint pinch bolt loose.
TI G
HTEN the steering column universal joint

pinch bolt. For additi onal information,
REFER to Section 211
-0 4
Steering Column
.
Incorre
ct
toe adjustment.

ADJUS
T as necessary. For additional
information,
REFER to Section 204
-00 Sus
pension
Sy
ste
m
- General

Information
.
Loose or worn rear
susp
ension.
TIGHTEN
loose, or IN
STALL new rear
suspension components. For additional information,
REFER to Section 204
-0 2
Rear Suspension
.
Vehicle t
e
nds to pull to one
side when driven on a level surface
Incorrect ti
re pressure.
Incorrect
ti
re size or
different tire/tread type.
Uneven tire wear
CHECK and ADJ
UST the tire pressure. For
additional information,
REFER to Section 204
-0 4
Wheels and Tires
. IN
ST
ALL a new tire as necessary. For
additional information,
REFER to Section 204
-04
Wheels and Tires
.
Vehicl

e is unevenly loaded
or overloaded.
Adjust the load
.
Incorre
ct
toe adjustment.

ADJUS
T as necessary. For additional
information,
REFER to Section 204
-00 Sus
pension
Sy
ste
m
- General

Information
.
Dam
a
ged front suspension

components.
I N
STALL new front suspension components
as necessary. For addi tional information,
REFER to Section 204
-01 Fron
t Suspension
.
Damaged rear
suspen
sion
components.
INST ALL ne
w rear suspension components
as necessary. For addi tional information,
REFER to Section 204
-0 2
Rear Suspension
.
Steeri
ng gear val
ve effort
out of balance.
SHIF T the
transmission into NEUTRAL while
driving at no more than 30 miles/hour (50 km/h) and turn the ignition to position I
(engine OFF-coasting). If the vehicle does
not pull with the engine off, INSTALL a new steering gear. For additional information,
REF E
R to Section 211
-0
2
Power Steering
. If t
he
vehicle does drift with the engine off,
CROSS SWITCH front wheel assemblies.
If the
vehicle pulls to
the opposite side,
SWITCH wheels that were on the rear to the
same side on the front.
If the v
ehicle pull dire
ction is not changed,
CHECK the front susp ension components
and toe adjustments. For additional information,
REFER to Section 204
-01 Fron
t Suspension
.
Chec
k
the front and rear
brakes for correct operation.
ADJUS
T as necessary. For additional
information,
REFER to Section 206
-0 0
Brake System
-
General Informati on.
Check fo
r bent rear
INST
ALL ne
w rear suspension components

sus
pension components
and for damaged coil springs in the front suspension.
as necessary. For addi tional information,
REF
ER to Section 204
-0
2 Rear Suspension
. I

NSTALL new front suspension components
as necessary. For addi tional information,
REFER to Section 204
-01
Front Suspension
.
Chec

k the rear suspension

for loose or worn
suspension components.
TIGHTE
N or INSTALL new components as
necessary. For additi onal information,
REFER to Section 204
-0
2 Rear Suspension
.
Incorre

ct underbody
alignment.
CHECK
underbody alignment. For additional

information,
REFER to Section 502
-00
Uni
-Body, Subframe and M

ounting System
.
Poor r

eturnability of the
steering
Lower steeri
ng column
interference.
CHECK
the steering co
lumn is free from
interference from the en gine harness, sound
proofing or the floor covering.
Incorrect
tire pressure.
CHECK
and ADJUST the tire pressure. For
additional information,
REFER to Section 204
-0
4 Wheels and Tires
.
Incorrect

tire size or type.
IN
STALL a new tire as necessary. For
additional information,
REFER to Section 204
-0
4 Wheels and Tires
.
Steeri

ng column upper
shroud fouling on the steering wheel.
CHECK
steering column upper shroud for
fouling. ADJUST as necessary.
Steeri
ng column universal
joints binding.
IN
STALL a new steering column. For
additional information,
REFER to Section 211
-0
4 Steering Column
.
Steeri

ng column shaft floor

seal binding.
CHE
CK the steering column shaft floor seal
for correct fitm ent and REFIT as necessary.
Steeri
ng column shaft floor

seal may be torn.
IN
STALL a new steering column shaft floor
seal as necessary.
Bin
ding or damaged tie-
rods.
CHECK
tie-rod end for excessive wear or
tightness in ball joint. INSTALL a new tie- rod end. For additional information,
REFER to Section 211
-0
3 Steering Linkage
.
D

amaged or worn front
suspension components.
I
NSTALL new front suspension components
as necessary. For addi tional information,
REFER to Section 204
-01
Front Suspension
.
Incorre

ct toe adjustment.

AD
JUST as necessary. For additional
information,
REFER to Section 204
-00
Suspension
Sy

stem
- General
Information
.
Excessive steeri

ng efforts
required during low speed
manoeuvring and/or during parking manoeuvres
Low power steer
ing fluid.

CHE
CK steering system
for signs of steering
fluid loss.
BLEE
D the power steering system. For
additional information,
REFER to Section 211
-0
0 Steering System
- General Informati

on
.
Damaged accessory driv

e
belt tensioner.
INST
ALL a new accessory drive belt
tensioner.
Hose or cooler li
ne
restriction.
CHECK
hose or cooler lines for correct
routing.
INST
ALL a new hose as necessary.
Fl

uid aeration.
BLEE
D the system. For additional
information,
REFER to Power Steering System Bleeding

in t
his section.

Steeri
ng transducer not
closed - no feed voltage.
CHECK
the steering transducer circuit. For
additional information, REFER to the wiring diagrams.
Carry ou
t the electrical checks and tests.
For additional information, REFER to the
Electrical Checks and Tests in this section.
Steeri
ng transducer not
closed - cable fault.
CHECK
the steering transducer circuit. For
additional information, REFER to the wiring diagrams.
Carry ou
t the electrical checks and tests.

No
ise
S
teering heavy operation in
one direction
F
aulty rotary valve/seal.
addi
tional information, REFER to the Power
Steering Pressure Test in this section.
INST
ALL a new steering
gear as necessary.
For additional information,
REFER to Section 211
-0
2 Power Steering
.
Ti

re fouling on the wheel
arch liner.
CHECK for
clearance be
tween the tire and
the wheel arch liner.
R
emove and refit the wheel arch liner or
INSTALL a new wheel arch liner as necessary.
S
teering heavy operation in
both directions
Low power steer
ing fluid.

CHE
CK steering system
for signs of steering
fluid loss.
BLEE
D the power steering system. For
additional information,
REFER to Section 211
-0
0 Steering System
- General Informati

on
.
Ai

r in power steering
system.
CHECK
the power steering pump for signs o
f steering fl

uid loss.
INST

ALL a new power steering pump as
necessary. For additi onal information,
REFER to Section 211
-0
2 Power Steering
.
Fluid loss at the power
steering pump shaft seal.
CHECK
the power steering pump for signs o
f steering fl

uid loss.
INST

ALL a new power steering pump as
necessary. For additi onal information,
REFER to Section 211
-0
2 Power Steering
.
Power steeri

ng fluid
delivery pressure or flow too low.
CHECK
the power steering pump for signs o
f steering fl

uid loss.
CHECK

the power stee
ring pressure. For
additional information, REFER to the Power Steering Pressure Test in this section.
INST
ALL a new power steering pump as
necessary. For additi onal information,
REFER to Section 211
-0
2 Power Steering
.
Steeri

ng operation varies
from heavy to light when
driving at constant speed
Lower steeri
ng column
interference.
CHECK
the steering co
lumn is free from
interference from the en gine harness, sound
proofing or the floor covering.
Incorre
ct sp
eedometer
signal.
CHECK
the speedo circ
uit. For additional
information, refer to the wiring diagrams.
Steeri
ng transducer
cable/connection faulty or grounded.
CHECK
the steering transducer circuit. For
additional information, refer to the wiring diagrams.
Carry ou
t the electrical checks and tests.
For additional information, REFER to the
Electrical Checks and Tests in this section.
Steeri
ng wheel varies from
light to heavy two times per revolution
Lower steeri
ng column
interference.
CHECK
the steering co
lumn is free from
interference from the en gine harness, sound
proofing or the floor covering.
Steeri
ng column universal
joints binding.
IN
STALL a new steering column. For
additional information,
REFER to Section 211
-0
4 Steering Column
.
Seized or damaged
ste
ering components.
CHECK
for wear or failure of suspension
bushes and ball join ts. For additional
information,
REFER to Section 204
-00
Suspension
Sy

stem
- General
Information
.
Cond

ition
Possib
le Sources
Acti
on
Acce

ssory drive
belt squeal
Incorre
ct accessory drive belt

tension or accessory drive belt glazed.
CHECK
accessory drive belt condition and INSTALL a
new accessory drive belt as necessary. For additional
information,
REFER to Section 303
-0
5 Accessory Drive
.
Chir

p noise in
the steering pump
Loose or worn accessory dr
ive belt.
CHECK
accessory drive belt condition and INSTALL a
new accessory drive belt as necessary. For additional
information,
REFER to Section 303
-0
5 Accessory Drive
.

Input speed is monitored by the TCM with a rationality check being made against output speed. A fault will be flagged if the
indicated input speed exceeds 7400 rpm. Additionally, a failure judgement will be made if the indicated input speed is <160
rpm with engine speed >608 rpm and output speed >224 rpm
The procedure is similar for the output sp eed diagnostic. A fault (non OBDII) will be flagged if the indicated input speed
exceeds 6712 rpm. Additionally a failure judgement will be ma de if the indicated output speed is <160 rpm and the average
road wheel speed exceeds 100 rpm.
Under normal circumstance s after the output speed diagnost ic fault code has been set, the TCM uses rear wheel speed
information to compute its calculations, this has no effect on transmission operation. However, should a second fault occur,
in the ABS system, thus making rear wheel speed information unavailable, an additional fault code will be logged.
Control Systems
Introduction
Gear selection is achieved by controlling the flow of transmission fluid to internal multi-disc clutches.
The three solenoid valves direct the transmission fluid flow to the selected clutches and the pressure regulators control the
fluid pressure to each component. One pr essure regulator serves as a master pressure control for the entire system and a
second is used exclusively for torque converter clutch lock-up operation.
The TCM controls the internal components thus determining gear selection and shift pattern.
In the event of an electronic system fault the basic function s Park, Reverse Neutral and Drive Fourth are retained by the
hydraulic system.
Transmission Control Module (TCM)

The TCM is located in the same housing as th e ECM and is accessed in the same manner.
The TCM performs several 'self check' procedur es to ensure correct operation. It is possible due to the nature of these faults
that the module will fail to communicate with other nodes. However, condemnation of the TCM should not take place until
any CAN or power supply related problems have been resolved.
There are three self check procedures for the TCM. 1. 1. Check on ROM by calculatin
g a checksum and comparing this with a known stored value.