1998 JAGUAR X308 air control

Parking Brake and Actuation - P
arking Brake Control
Re
mo
val and Installation
Remov
a
l
W
A
RNING: BRAKE DUST, IF INHALED CAN DAMAGE YOUR
HEALTH. ALWAYS REMOVE BRAKE DUST USING A VACUUM
BRUSH. DO NOT USE A COMPRESSED-AIR LINE TO DISPERSE BRAKE DUST INTO THE ATMOSPHERE.
CAUTION: Replacement of nuts and bolts: Various thread-locking devices are used on nuts and bolts throughout the
vehicle. These devices restrict the number of times a nut or bolt can be used. See section 100-00 for information.
1. Position vehi cl
e on a four-post lift.
2. Release parking brake.

3. Releas
e tension on parking brake cable.
Slacken bu

t do not remove adjustment nut.

4. Releas
e parking brake cable.
Remo

ve clip.
Re
mo
ve clevis pin.
5. Remove driver seat for access . Refer to operation 76.70.01.
6. Remove trim from hand lever. Refer to operation 76.13.63.
7. Carefully reposition carpet from around hand lever for access.

8. Disconnect park ing-br
ake, warning-light switch connector.
9. Remove hand lever from vehicle.

The t
andem master cylinder contains two in
dependent pistons, fluid pressure to each brake circuit is controlled by its own
individual piston. Brake fluid is supplied to the master cylinder by the reservoir, which is divided into two sections to preve nt
total fluid loss should one of the circuits fail. A port situated at the bottom of each section of the reservoir supplies the f luid
to each piston.
The fluid reservoir has a fluid-le vel indicator switch installed, which operates when the fluid level is low, causing the brake
fluid level warning-lamp to illuminate.
Bra
ke Caliper
The brake
calipers are of the single piston
type. The caliper carrier, which is secured to the vertical link by two bolts, carr ies
the single-piston caliper housing. The cali per housing is secured to the caliper carrier by two guide-pins and an anti-rattle
spring. When the brakes are applied, the caliper-housing piston pushes the brake pad in front of it, to wards the brake disc.
This movement forces the calipe r housing to move along the guid e-pins, in the opposite direction of the piston, to apply the
second brake pad.
Br
embo Brake Caliper
The four
cylinder brake caliper is rigidly attached to the vert
ical link via an anchor bracket. The caliper is a split assembly
with each side of the caliper, housing two pistons. The two-pairs of opposed pistons act direct ly on the brake pads mounted
one each side of the disc.




Mast
er Cylinder and Reservoir

Anti-Lock Control - Anti-Lock Control
Description and Operation


Wheel Spe
ed Sensors
Each
wheel is monitored by a wheel speed se n
sor, to detect the speed of movement of
a toothed gear that is driven by the
wheel. Signal's generate d by the toothed gear passing th e sensor are sent to the ABS/TCCM to communicate the speed of
wheel rotation and any rapid change of wheel speed.
The frequency of the sinusoidal output voltag e signal from the sensor, is proportional to road wheel rotational speed and the
number of teeth on the toothed gear. The amplitude of the volt age is dependent upon the 'air gap' between the sensor and
toothed wheel, therefore it is important that this preset gap remains clear and undisturbed.
Ite
m
De
scr
iption
1Pe
dal Housi
ng / Booster - refer to 206-07
2Vac
u
um Hose - refer to 206-07
3Mas
t
er Cylinder / Reservoir - refer to 206-06
4Pri
m
ary Brake Circuit - refer to 206-06
5Sec

ondary Brake Circuit - refer to 206-06
6Hydraulic

Pump / Motor Unit
7ABS/Traction

Control Control Module (ABS/TCCM)
8Hydraulic Cont

rol Unit (HCU)
6/
7/
8
Br
ak
e Control Modulator
9Brake
Di
sc - refer to 206-03 or 206-04
10Brake
Cali
per - refer to 206-03/206-04
11Wh
ee
l Speed Sensor
12ABS Warning Lamp
13Brake
Fl
uid Level Warning-Lamp - refer to 206-06

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

Make sure the ignition is turned off. 1
Meas
ure the resistances between LF27,
pins 08 and 24 (B) and ground.
2
Are
the resistances less than 5 ohms?
Yes The power and ground supplies to the module are ok . Recheck the DTCs for codes indicating a fault
elsewhere.
No Repair the high resistance circui t. Refer to the electrical guides. Clear the DTC, check for normal
operation.
PINPOINT TE
ST B : CHECK THE RIGHT-HAND FRONT WSS AND CIRCUITS
•
NOTE: Check connectors and pins for damage/corrosion
(see visual inspection).
•
NOTE: Check the WSS ring condition, whee
l bearing etc. Before beginning pinpoint test s refer to the visual inspection.
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS
B1: CHECK

THE WSS OUTPUT
Disc

onnect the ABS sensor connector, FR01.
1
Connec

t a multimeter set
to read alternating curr ent volts (AC volts) between pins 1 and 2 of the
sensor.
2
Spin
the wheel by hand and check the meter display.
3
Doe

s the sensor generate a voltage?
Yes GO to B2
.
No

If the WSS ring is in good condition, install a new WSS.
REFER to: Front Wheel Speed Sensor
(20
6-09 Anti-Lock Control, Removal and Installation).
B2:

CHECK THE WSS SIGNAL CIRCUIT CONTINUITY
Make sure the ignition is off. 1
Di

sconnect the ABS module connector, LF27.
2
Meas

ure the resistance between LF27
, pin 03 (Y) and FR01, pin 02 (Y).
3
I
s the resistance less than 5 ohms?
Yes GO to B3
.
No

Repair the high resistance circui t. This circuit includes intermediate connector, LF02. Refer to the
electrical guides. Clear the DTC, check for normal operation.
B3:
CHECK THE WSS RETURN CIRCUIT CONTINUITY
Meas

ure the resistance between LF27
, pin 04 (G) and FR01, pin 01 (G).
1
I
s the resistance less than 5 ohms?
Yes The WSS and circuits are OK. Check for DTCs indicating a possible module failure.
No Repair the high resistance circui t. This circuit includes intermediate connector, LF02. Refer to the
electrical guides. Clear the DTC, check for normal operation.
P
INPOINT TEST C : CHECK THE LEFT-HAND FRONT WSS AND CIRCUITS
•
NOTE: Check connectors and pins for damage/corrosion
(see visual inspection).
•
NOTE: Check the WSS ring condition, whee
l bearing etc. Before beginning pinpoint test s refer to the visual inspection.
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS
C1

: CHECK THE WSS OUTPUT
Disc

onnect the ABS sensor connector, FL01.
1
Connec

t a multimeter set
to read alternating curr ent volts (AC volts) between pins 1 and 2 of the
sensor.
2
Spin
the wheel by hand and check the meter display.
3
Doe

s the sensor generate a voltage?
Yes GO to C2
.
No

If the WSS ring is in good condition, install a new WSS.
REFER to: Front Wheel Speed Sensor
(20
6-09 Anti-Lock Control, Removal and Installation).
C2

: CHECK THE WSS SIGNAL CIRCUIT CONTINUITY

Make sure the ignition is off. 1
Disc
onnect the ABS module connector, LF27.
2
M
e
asure the resistance between LF27, pin 17 (W) and FL01, pin 02 (W).
3
I
s
the resistance less than 5 ohms?
Yes GO to C3
.
No
Re
pair the high resistance circui
t. This circuit includes intermed iate connector, LF02. Refer to the
electrical guides. Clear the DTC, check for normal operation.
C3: CH
ECK THE WSS RETURN CIRCUIT CONTINUITY
Measure

the resistance between LF27, pin 18 (R) and FL01, pin 01 (R).
1
Is

the resistance less than 5 ohms?
Yes The WSS and circuits are OK. Check for DTCs indicating a possible module failure.
No Repair the high resistance circui t. This circuit includes intermediate connector, LF01. Refer to the
electrical guides. Clear the DTC, check for normal operation.
PI
NPOINT TEST D : CHECK THE RIGH
T-HAND REAR WSS AND CIRCUITS
•
NOTE: Check connectors and pins for damage/corrosion
(see visual inspection).
• NO
TE: Check the WSS ring condition, whee
l bearing etc. Before beginning pinpoint test s refer to the visual inspection.
TES
T
CONDITIONS
D E
TAILS/RESULTS/ACTIONS
D1: CHECK

THE WSS OUTPUT
Disc
onne
ct the ABS sensor connector, RA02.
1
Connec
t
a multimeter set
to read alternating curr ent volts (AC volts) between pins 1 and 2 of the
sensor.
2
Spin
the wheel by hand and check the meter display.
3
Doe
s
the sensor generate a voltage?
Yes GO to D2
.
No
If
the WSS ring is in good condition, install a new WSS.
REFER to: Rear Wheel Speed Sensor
(206-0
9 Anti-Lock Control, Removal and Installation).
D
2
: CHECK THE WSS SIGNAL CIRCUIT CONTINUITY
Make sure the ignition is off. 1
Disc

onnect the ABS module connector, LF27.
2
Measure t

he resistance between LF27
, pin 07 (O) and RA02, pin 01 (O).
3
Is
the resistance less than 5 ohms?
Yes GO to D3
.
No Re
pair the high resistance circui
t. This circuit includes intermed iate connector, LA02. Refer to the
electrical guides. Clear the DTC, check for normal operation.
D3:
CHECK THE WSS RETURN CIRCUIT CONTINUITY
Meas
ure t
he resistance between LF27
, pin 06 (Y) and RA02, pin 02 (Y).
1
Is
the resistance less than 5 ohms?
Yes The WSS and circuits are OK. Check for DTCs indicating a possible module failure.
No Repair the high resistance circui t. This circuit includes intermediate connector, CA09. Refer to the
electrical guides. Clear the DTC, check for normal operation.
PI
NPOINT TEST E : CHECK THE LEFT-HAND REAR WSS AND CIRCUITS
•

NOTE: Check connectors and pins for damage/corrosion
(see visual inspection).
• NO
TE: Check the WSS ring condition, whee
l bearing etc. Before beginning pinpoint test s refer to the visual inspection.
TES
T
CONDITIONS
D E
TAILS/RESULTS/ACTIONS
E1
: CHECK THE W
SS OUTPUT
Disc
onne
ct the ABS sensor connector, LA02.
1
Connec
t
a multimeter set
to read alternating curr ent volts (AC volts) between pins 1 and 2 of the
sensor.
2

Spin
the wheel by hand and check the meter display.
3
Doe

s the sensor generate a voltage?
Yes GO to E2
.
No

If the WSS ring is in good condition, install a new WSS.
REFER to: Rear Wheel Speed Sensor
(20
6-09 Anti-Lock Control, Removal and Installation).
E2

: CHECK THE WSS SIGNAL CIRCUIT CONTINUITY
Make sure the ignition is off. 1
Di

sconnect the ABS module connector, LF27.
2
Meas

ure the resistance between LF27
, pin 21 (U) and LA02, pin 01 (U).
3
I
s the resistance less than 5 ohms?
Yes GO to E3
.
No

Repair the high resistance circui t. This circuit includes intermediate connector, LA02. Refer to the
electrical guides. Clear the DTC, check for normal operation.
E3
: CHECK THE WSS RETURN CIRCUIT CONTINUITY
Meas

ure the resistance between LF27
, pin 22 (U) and LA02, pin 02 (U).
1
I
s the resistance less than 5 ohms?
Yes The WSS and circuits are OK. Check for DTCs indicating a possible module failure.
No Repair the high resistance circui t. This circuit includes intermediate connector, CA29. Refer to the
electrical guides. Clear the DTC, check for normal operation.
P
INPOINT TEST F : CONT
ROLLER AREA NETWORK (CAN) INTEGRITY TEST
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS
F

1: CHECK THE NETWORK INTEGRITY
FROM THE DIAGNOSTIC SOCKET
M
easure the resistance between pins 06 (Y) and 14 (G) of the diagnostic socket.
1
I

s the resistance 60 ohms?
Yes The CAN system is OK. Check for DTCs indicating a fault elsewhere.
No Check the CAN system for open an d short circuits. Refer to the electrical guides. Clear the DTC,
check for normal operation.

Fo
r additional information, REFER to the
Electrical Checks and Tests in this section.
Steering control
module
(SCM) defective.
CHECK
the SCM and INSTALL a new SCM as

necessary.
Power steeri ng f
luid
delivery pressure or flow too low.
CHECK
the power stee
ring pressure. For
additional information, REFER to the Power Steering Pressure Test in this section.
INSTALL a ne
w power steering pump as
necessary. For additi onal information,
REFER to Section 211
-0 2
Power Steering
.
Internal steering gear
leakage.
CHECK
the power stee
ring pressure. For
additional information, REFER to the Power Steering Pressure Test in this section.
INSTALL a ne
w steering
gear as necessary.
For additional information,
REFER to Section 211
-0 2
Power Steering
.
Steeri
ng operati
on is very
heavy when driving, but when stationary
manoeuvring is good
Steering transducer open earl
y.
CHECK

steering transducer and INSTALL a
new steering transducer as necessary.
Carry out th
e electrical checks and tests.
For additional information, REFER to the
Electrical Checks and Tests in this section.
Steering transducer open
early,
steering control
module (SCM) fault.
CHECK
SCM and INSTALL a new SCM as
necessary.
Steering transducer open
earl
y, speedo signal error.
CHECK
speedo
circui
t. For additional
information, REFER to the wiring diagrams.

Steeri ng operati
on is very
light when driving, but when
stationary manoeuvring is good
Steering transducer not
o
pen, (no power steering
fluid flow).
CHECK
the power steering fluid condition.
For additional information, REFER to the
Power Steering Fluid condition check in this section.
Steering transducer not o
pen, steering control
module (SCM) fault.
CHECK
the SCM and INSTALL a new SCM as

necessary.
Carry out th
e electrical checks and tests.
For additional information, REFER to the
Electrical Checks and Tests in this section.
Steering transducer not
o
pen, speedo signal error.
CHECK

the speedo circ
uit. For additional
information, REFER to the wiring diagrams.

CHECK
the power steering
fluid low pressure pipe for restricted flow.
INSTALL a ne
w power steering fluid low
pressure pipe.
S t
eering heavy operation
during rapid manoeuvring
Ai r i
n power steering
system.
CHECK for an air l
eak into the power
steering system and re pair as necessary.
BLEED the
power steering system. For
additional information,
REFER to Power Steering System Bleeding
- in t hi
s section.
Fluid loss at the power
steering pump shaft seal.
CHECK the power steer
ing pump for signs o
f steering fl
ui
d loss.
INST
ALL a ne
w power steering pump as
necessary. For additi onal information,
REFER to Section 211
-0 2
Power Steering
.
Power steeri
ng f
luid
delivery pressure or flow too low.
CHECK the power steer
ing pump for signs o
f steering fl
ui
d loss.
CHECK

the power stee
ring pressure. For
additional information, REFER to the Power Steering Pressure Test in this section.
INSTALL a ne
w power steering pump as
necessary. For additi onal information,
REFER to Section 211
-02
Power Steering
.
Lower steeri
ng col
umn
interference.
CHECK
the steering co
lumn is free from
interference from the en gine harness, sound
proofing or the floor covering.
Incorrect steering geometry. CHE
CK the front wheel alignment. For
additional information,
REFER to Section 204
-00 Sus
pension
Sy
ste
m
- General

Information
.
CHECK

the power stee
ring pressure. For