1998 JAGUAR X308 speed control

Tacho
meter
TACHA
ci
rcuit that provides input for
an electronic tachometer display
Thermal Vacuu
m Valve
TVVControls vacuum l
e
vels or
routing based on temperature
Throttle
Body
TBDe
vi
ce containing the throttle
Throttl
e
Position
TP
Throttl
e
Position Sensor
TPSInterprets throttl
e

position and movement to iden tify idle, acceleration and
full-power demands
Top Dead CenterTDC
Torque Converter C
lutch
TCC
To
tal
indicator reading
TIRThe t
o
tal indicated movement on a DTI with the test piece rotated through
360°
Transm
ission Control
Module
TCMControls
the shifting pattern
of the (automatic) transmission
Transm
ission Control
Switch
TCSModifi es
the operation of electronically controlled transmissions
Transmission Oil
TemperatureTOTIndi
cat
es temperature of transmission fluid
Transmission RangeTRThe ran
g
e in which the transmission is operating
Transmission Spe
e
d
Sensor
TSSIndi cat
es rotational speed of transmission output shaft or turbine shaft
V
Vacuu
m
Solenoid Valve
VSVVacuu
m
operated valve used in the speed control system
Vacuu
m
Solenoid Valve
(atm)
VSV VAVacuu m
atmospheric valve used in the speed control system
Vacuu
m
Solenoid Valve
(rel)
VSV VRVacuu m
release valve used in the speed control system
Vacuu
m
Solenoid Valve
(vac)
VSV VVVacuu m
valve used in the speed control system
Variable Valve TimingVVTA
s
ystem by which the relationship of the crankshaft and camshaft may be
altered during engine running
Vehi cl
e Battery Adapter
VBAProvide
s
electrical power to the PDU
and supplies a battery reference level
Vehicl
e Condition Monitor
VCMInst
rum
ent panel display which warns of faults
Ve
hic
le Emission Control
Information Label
VECI Label
Vehi cl
e Identification
Number
VINN u
mber assigned to the vehicle by the manufacturer, primarily for licensing
and identification purposes
Vehi cl
e Interface Adapter
VIAExtends the
PDU ca
pability and provid
es a parallel interface to vehicle
harnesses and ECMs
Vehicle Spe e
d Sensor
VSSSens
or which provides ve
hicle speed information
Viscosity In
dexVI
Voltage RegulatorVRDe
vice which regulates the variable output voltage of a generator
W
Wat
tWSI unit of power (1 hp = 7
45.7 watts)
W
i
de Open Throttle
WO
TFu
ll throttle position

O
ne locking wheel nut is fitted to each road wheel and can on
ly be removed by using the correctly coded socket. For road
wheels with exposed wheel nuts, each locking wheel nut is provided with a cover, which is removed using the cover removal
tool.
Locking wheel nuts have different coded keyway combinations with corresponding coded sockets. The correct socket, and
cover removal tool are supplied with the vehicle toolkit. Sets of sockets are available to Jaguar dealers.
Temporary Spare Wheel
•
NOTE: When using this type of spare wheel note that:
Speed

must not exceed 80 km/h (50 mph).
The normal ro

ad wheel must be reinstalled as soon as possible.
On

ly one temporary wheel may be installed to the vehicle.
Tracti

on control (where fitted
) must be switched OFF.
In certain markets, the spare wheel supplied with the vehicle is of the temporary-use type, it is narrower than the normal
road wheel and takes up less room in the luggage compartment.
Tire
s
The
radial ply tires shown in the 204-04
Specification Section are recommended by Jaguar to meet the high speed
performance of the vehicle. Only tires of identical specification may be fitted as replacements. Unde r no circumstances must
cross-ply tires be fitted.
Tire Inflation Pressures
Al
l recommended tires, including winter tire
s, must be inflated to the pressures shown in the 204-04 Specification Section.
Inflation pressures must only be checked when the tires are cold.
Tire Replac
ement and Wheel-Interchanging
W
hen renewal of tires is necessary, it is
preferable to fit a complete set. If two replacement tires are fitted (to one axle),
they must be of the same manufacturer and type as those on the other axle.
No attempt must be made to interchange wh eels from the front to the rear or vice-versa, as wear produc es a characteristic
pattern on each tire depending upon its po sition on the vehicle. If this position is changed after wear has occurred, the
performance of the tire w ill be adversely affected.
It should be remembered that new tires must be balanced befo re installing to the vehicle.
Win
ter Tires
•
NOTE: Speed must not exceed 210 km/h (131 mph) when winter tires are installed.
Jaguar recommended winter tires as specified in 204-04 Specification Section must only be fitted in complete four-wheel
sets of the same type and size.
Snow Chains and Spike Spider Traction System

Jagu
ar recommended snow chains, must on
ly be installed when using 16 inch wheels with 255/60 R16 winter tires.
• NOTE: When using snow chains or the spike spider traction system, note that:
Snow ch
ains and the spike spider
traction system must only be fitted to the rear wheels.
O
nly Jaguar recommended snow chains and spik
e spider traction system must be used.
The m
aximum permissible speed with winter tires and snow chains or the spike spider traction system fitted is 48
km/h (30 mph).
Tracti
on control (where fitted) must be
switched OFF when using snow chains or the spike spider traction system.

W
heels and Tires - Wheels and Tires
D
iagnosis and Testing
General Not

es
1.
1. Factory in
stalled tires and wheels are designed to provide optimum ride and ha
ndling characteristics when inflated
to the recommended inflation pressures, with vehicle loads not exceeding the full-rated load capacity.
2. 2. Correct tire pressures and driv ing technique have an important influence on tire life. Heavy cornering, excessively
rapid acceleration and unnecessary sharp braking increase tire wear.
3. 3. Replacement tires should follow the recommended:
Size
.
Speed

rating.
Load range. Radial c

onstruction type.
4. 4. The use of any other size or type of wheel / tire may seriously affect:
Safety. Ri
de.
Handlin

g.
Speed

ometer / odometer calibration.
Vehi

cle ground clearance.
Ti

re clearance between
body and chassis.
Wh
eel bearing life.
Brake cooli

ng.
5. 5. Wheels must be renewed when:
Impact damaged. Heavil
y corroded.
Porous W

heel stud holes or se
ats become damaged.
They h
ave excessive radial or lateral runout.
Safety Notes
• WAR

NINGS:
DO NOT MIX DIFFERENT TYPES OF TIRES ON THE SAM E VEHICLE, HANDLING MAY BE SERIOUSLY AFFECTED
RESULTING IN LOSS OF CONTROL.
DO NOT MIX DIFFERENT TYPES OF TIRES ON THE SAM E VEHICLE, HANDLING MAY BE SERIOUSLY AFFECTED
RESULTING IN LOSS OF CONTROL.
A TIRE AND WHEEL MUST ALWAYS BE CORRECTLY MATCHED. WIDER OR NARROWER TIRES THAN RECOMMENDED
COULD CAUSE DANGER THROUGH SUDDEN DEFLATION.
WHEN USING THE TEMPORARY SPARE WHEEL, SPEED MUST NOT EXCEED 80 KM/H (50 MPH). DRIVE WITH CAUTION
AND REPLACE WITH THE SPECIFIED WHEEL / TIRE ASSEMBLY AS SOON AS POSSIBLE.
TRACTION CONTROL (IF AVAILABLE) MUST NOT BE ENGAGED WITH THE TEMPORARY SPARE WHEEL FITTED.

R
equire no adjustment and are non-serviceable items.
Accelerometers


The three accelerometers:
Sense veh
icle body movement.
Gen

erate an analogue voltag
e (maximum +5 volts) proportional to body movement.
Pr
ovide inputs to the adapti
ve damping control module.
The two vertical acce lerometers are mounted on the bulkhead and in the trunk.
The lateral accelerometer is mounted in the ECM housing.
Ada
ptive Damping Control Module (ADCM)

The ADCM
:
Is

mounted on the fascia support bracket.
Controls the four adaptiv

e dampers in re
sponse to analogue and digital inputs.
It
em
De
scription
1Battery su

pply
2Ignition su

pply
3Ground
4Input from verti

cal accelerometer, front
5Input from verti

cal accelerometer, rear
6Input from later

al accelerometer
7F

ootbrake operation signal
8Vehi

cle speed input
9D

amper control signals
10Ou

tput to message center
11D

iagnostic connector serial link

Is hard-wi
red to the instrume
nt cluster message center.
Is hard
-wired to the J1962 diagnostic connector.
Op
era
tion
Th
e
system selects the soft or
firm damper setting according to the current ro ad and driving conditions, to optimise vehicle
ride and handling.
With the vehicle stationary, the dampers are in the firm setting, but will normally switch to the soft setting when the vehicle
exceeds 8 km/h (5 mile/h); all dampers are switched simultaneously.
Sudden movement of the vehicle body, in response to road inputs, is detected by the vertical accelerometers, and the ADCM
switches the dampers to the firm setting to give improved damping of the resultant oscillations.
When cornering forces are detected by th e lateral accelerometer, the ADCM switches the dampers to the firm setting to
reduce the roll rate an d improve wheel control.
After the event has passed, the dampers revert to the soft setting.
When the footbrake is applied, the ADCM re ceives a signal and calculates the rate of vehicle deceleration. If the deceleration
rate is greater than a certain threshold, the dampers are switched to the firm setting to reduce the pitch rate and improve
wheel control.
If a system failure occurs, the ADCM grounds the output line to the instrument cluster message center, which displays a
text warning SUSPENSION FAULT and illuminates the amber warning lamp. Under fault conditions the system always fails to
the firm setting, so that the vehicle will be safe to drive un der all road and driving conditions.
Connector Pin Identity Chart for EM068

Pin
Number
Ci
rcui
t
Circuit Functi
on
1System erro
r output to instrument
cluster
2Not
used
3O/
P a
ccelerometer ground
4 to

9
Not
used
10K-
li
ne to diagnostic socket
11Ignition su
pply +12V
12Not
used
13Control signal (+ve) output
to l
eft-hand rear damper
14Control signal (+ve) output
to right-hand front damp
er
15Control signal (+ve) output
to right-hand rear
damper
16
a
nd 17
No
t
used
18Ground
19No
t
used
20Lateral
accelerometer i
nput
21Front vertical ac
celerometer in
put
22Rear vertical
acce
lerometer input
23No
t
used
24R
o
ad speed input from
instrument cluster
25Power output +5V to suppl y accelerometers
26Brake peda
l input

Brake System - General Inform
ation - Brake System
D
iagnosis and Testing
Principles of Operations
The brake system operates by transferring effort applied to th e brake pedal, by the driver to the brakes at each wheel.
The braking effort is distributed to each wheel, using a hydraulic system. The system is assisted using a vacuum brake
booster that reduces pedal effort for a given hydraulic pressure. The parking brake operates on the rear wheels and is
applied using a hand operated control.
I
nspection and Verification
•
NOTE: Prior to carrying out any diagno
sis, make sure that the brake system warning indicator is functional.
Visually examine the front and rear tire and wheel assemblies for damage such as un even wear patterns, tread worn out or
sidewall damage. Verify the tires are th e same size, type and, where possible, same manufacture. Replace the damaged
wheel or excessively worn tire. For a dditional information, refer toSection 204
-0
4 Wheels and Tires
.
W
heels and tires must be cleared of an
y foreign matter and tire pressures ad justed to the correct specification.
If the tires exhibit uneven wear or feathering, the cause must be corrected. Check the steering and suspension components
for damage or wear and, if ne cessary, check and adjust front wheel alignment. For additional information, refer toSection
204
-00 Suspen
sion System
- General Informati
on
.
Road Test


V
isual Inspection Chart
Carr

y out a road test to compare actual vehicle braking performance with the
performance standards expected by the
driver. The ability of the test driver to make valid compar isons and detect performance deficiencies will depend on
experience.
The driver should have a thorough knowledge of brake system operation and accepted general performance guidelines to
make good comparisons and de tect performance concerns.
An experienced brake technician will always establish a route that will be used for all br ake diagnosis road tests. The roads
selected will be reasonably smooth and level. Gravel or bump y roads are not suitable because the surface does not allow the
tires to grip the road equally. Crowned roads should be avoide d because of the large amount of weight shifted to the low set
of wheels on this type of road. Once th e route is established and consistently used, the road surface variable can be
eliminated from the test results.
Before a road test, obtain a complete description of the customer concerns or suspec ted condition. From the description, the
technician's experience will allow the te chnician to match possible causes with symptoms. Certain components will be
tagged as possible suspects while others wi ll be eliminated by the evidence. More importantly, the customer description can
reveal unsafe conditions which should be ch ecked or corrected before the road test. The description will also help form the
basic approach to the road test by narrowing the concern to specific components, vehicle speed or conditions.
Begin the road test with a general brake performance check. Keeping the description of the concern in mind, test the brakes
at different vehicle speeds using both ligh t and heavy pedal pressure. To determine if the concern is in the front or rear
braking system, use the brake pe dal and then use the parking brake control. If the condition (pull, vibration, pulsation)
MechanicalElectrical
Brake m
aster cylinder
Parkin
g brake switch
Brake ca

liper piston(s)
D
amaged or corroded wiring harness
Brake di

scs
B
rake master cylinder fluid level switch
Wh

eel bearin
gs
Brake pads
Power brake booster
Brake ped

al linkage
Boost

er vacuum hose
Tire

s
De

bris

Hydraulic Br
ake Actuation -
Hydraulic Brake Actuation
Description and Operation

The hydraulic brake system is split in to two independent circuits: the primary ci rcuit operates the front brakes and the
secondary circuit operates the re ar brakes. This type of system prevents comple te brake failure in the event of a brake tube
fracture.
The hydraulic brake system consists of the following components:

Ite
m
Descr
iption
1Pedal Housi

ng / Booster - refer to 206-07
2Vacu

um Hose - refer to 206-07
3Mast
er Cyl
inder / Reservoir
4Primary Brake Circu
i
t
5Secon
dary Brake Circuit
6Hydrauli c
Pump / Motor Unit - refer to 206-09
7ABS/Traction

Control Control Modu
le (ABS/TCCM) - refer to 206-09
8Hydraulic Cont
rol Unit (HCU) - refer to 206-09
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 or 206-04
11W
h
eel Speed Sensor - refer to 206-09
12ABS Warning Lamp -
refer to 206
-09
13Brake F
l
uid Level Warning-Lamp

Anti-Lock Control -
Lubri
cants, Fluids, Sealants and Adhesives
Torques
Brake Tube, Hoses and Bracket Torques
CAUTI
ON: 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.


UnitS
pecification
Brake flu

id
ITT Supe
r Dot 4
Com

ponent
Nm
Bol

t - front wheel speed sensor
8-
10
Bolt

- rear wheel speed sensor
8-
10
Bo

lt - hydraulic control unit to bracket
8-
10
Bolt -

hydraulic control unit bracket to body
10
-14
Hub rotor nut2

70-330
Com

ponent
Nm
Bleed n

ipple - front
4-
6
Bleed n

ipple - rear
8-1
1
Hose to fr

ont caliper
10
-14
Hose banjo to rear caliper -

bolt
30
-40
M1

0 hose locknut
15
-20
M10

brake tube female-nut
13
-17
M10

brake tube male-nut
13
-17
M12

brake tube male-nut
15
-20
M18

brake tube male-nut
22
-28
Brake tube clip retention

-bracket to body
4-
6