1998 JAGUAR X308 body

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

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.

Vibrati
on
Power steeri
ng
pump noisy
Low power steer i
ng fluid.
CHECK
steering system for s
igns of steering fluid
loss.
BLEE D the
power steering system. For additional
information,
REFER to Section 211
-0 0
Steering System
-
Ge n
eral
Informati
o
n
.
Power steeri
ng pump wor
n or

otherwise defective.
CHECK for leaks. R
EPAIR as necessary.
CHECK

the power steering pressure. For additional
information, REFER to th e Power Steering Pressure
Test in this section.
INST ALL a ne
w power steering pump as necessary.
For additional information,
REFER to Section 211
-0 2
Power Steering
.
Wh
in
e type noise

Aerated flui
d.
BLEE
D the
power steering system. For additional
information,
REFER to Power Steering System Bleeding
- in t h
is
section.
Power steering pump.
CHECK for leaks. R
EPAIR as necessary.
INSTALL a ne

w power steering pump as necessary.
For additional information,
REFER to Section 211
-0 2
Power Steering
.
No
i
se during
steering gear movement
Low power steer i
ng fluid.
CHECK
steering system for s
igns of steering fluid
loss.
BLEE D the
power steering system. For additional
information,
REFER to Section 211
-0 0
Steering System
-
Ge n
eral
Informati
o
n
.
Water co
n
tamination to the
power steering fluid.
DR AIN
the power steering system.
BLEE
D the
power steering system. For additional
information,
REFER to Section 211
-00
Steering System
-
Gen
eral
Informati
o
n
.
Cavi
tation due to restricted
po
wer steering feed hose.
CHECK

and reposition power
steering feed hoses and
INSTALL new hoses as necessary.
Continu o
us noise

Low power steer i
ng fluid.
CHECK
steering system for s
igns of steering fluid
loss.
BLEE D the
power steering system. For additional
information,
REFER to Section 211
-0 0
Steering System
-
Ge n
eral
Informati
o
n
.
Power steeri
ng pump dri
ve
loose.
CHECK
power steering coupli
ng and power steering
pump.
IN ST
ALL a new power steering coupling or power
steering pump as nece ssary. For additional
information,
REFER to Section 211
-0 2
Power Steering
.
Incorre
ct
accessory drive belt
tension or accessory drive belt glazed.
CHECK acc
essory drive belt condition and INSTALL a
new accessory drive belt as necessary. For additional
information,
REFER to Section 303
-0 5 Ac
cessory Drive
.
Power steeri
ng pump dri
ve
pulley loose.
CHECK
and TIGHTEN the power steering pump drive
pulley retaining bolts as necessary. For additional
information, REFER to Section 303
-03A En
gine
Coo
ling / 30 3-03
B Supercharger Cooling
.
Power steeri
ng pump
r
etaining bolts loose.
CHECK

the power steering pump retaining bolts and
TIGHTEN as necessary.
Power steering hose/pipe in c
ontact with the vehicles
body.
CHECK
and reposition powe
r steering hoses/pipes,
INSTALL new hoses/pipes as necessary.
Power steeri ng hose
r
estricted/twisted.
CHECK

and reposition powe
r steering hose, replace
hose as necessary.
Conditi
on
Possibl
e Sources
Actio
n
Loose/worn tie-
ro
ds.
INST
ALL a new tie-r
od end. For additional
information,

Hiss (Swish)
Hiss or Val
ve Hiss is a high-frequency so
und coming from the steering gear when the system is loaded. It is a rushing or
"swish" noise that doesn't change frequency with RPM. Hiss is the general noise generated by the flow of hydraulic fluid
through restrictions in the steer ing system. Restrictions include the rotary stee ring valve, power steering tubes, connectors,
tuning orifices, etc. Hiss can be air- borne and structure-borne, but the structure-borne path through the steering
intermediate shaft is usually dominant.
Moan (Groan)
Moan is the general structu r
e-borne noise of the steering system. Moan is primarily transmitted to the driver via the body
structure through the pump mount, engine mounts, power steering lines and power steering brackets. On some vehicles,
moan is a load humming noise, often present when the wheel is turned and the system is loaded. It may change frequency
with engine RPM and if the sy stem is loaded or unloaded.
Rack Knock (R
ack Slap)
CAU
T
ION: DO NOT attempt to adjust the stee
ring gear yoke. Failure to follow this instruction will result in the steering
gear warranty to become invalid.
Rack Knock is a rattle sound an d steering wheel vibration caused by separation of the steering gear and pinion while driving
over bumps. It is a structure-borne noise transmitted throug h the intermediate shaft and column. Rack knock can also be
heard as a "thump" or impact noise that occurs with the vehicle stationary when the steering wheel is released from a
loaded position and allowed to return to rest . Noise occurs with the engine on or off.
Rattles
Ra
ttles are noises caused by knocking or hitting with components in the steering system. Steering rattles can occur in the
engine compartment, the suspension, or the passenger compartment . Rattles can be caused by loose parts, movable and
flexible parts, and improper clearances.
Squea k
s/Scrapes
Squeaks/Scrapes are noises due
to fri
ction or component rubbi
ng anywhere in the steering system. Squeaks/Scrapes have
appeared in steering linkages and jo ints, in column components and in co lumn and steering wheel trim parts.
Weep
We
ep is an air-borne noise, occasionally
generated when turning the steering across lock at a constant rate. When present
on a vehicle the noise, once initiated can often be maintained across a large proportion of the available steering movement.
Whistle
Wh
istle is similar to hiss but is louder and of a higher frequency. It is also more
of a pure tone noise than hiss. Whistle is
air-borne and is generated by a high flow rate of hydraulic fluid through a small restriction.
Zip

Zip n
o
ise is the air-borne noise
generated by power steerin g pump cavitation when power steering fluid does not flow freely
through the suction hose from the rese rvoir to the pump. Zip primarily occurs during cold weather at start-up.
Steering System Vibrations and Harshne
ss
Buzz
Buzz is a tactile rotary vi

bration felt in
the steering wheel for slow steering inputs. Buzz can also be called a grinding feel
and it is closely related to grunt and is caused by high system gain with low damping. Buzz is generally excited during
parking manoeuvres with low to medium speed steering input.

Power Steering -
Lubric
ants, Fluids, Sealants and Adhesives
Capacities
Torques


UnitSp
ecification
PAS flu
i
d
De
xr
on 3
UnitLi
t
ers
PAS syste
m1,0
PAS reservoi
r0,4
Com p
onent
Nm
Rac
k
mountin
g brac
ke
t to suspension crossbeam
40
- 50
PAS pump to front mounti
ng bracket
22
-
26
P
AS pu
mp assembly to cylinder block
38
-
48
Pul
l
ey to PAS pump
18
-
24
Hi
gh pressure hose to PAS pump22 -
28
Rack
pipe latch plate bolt8.5 -
11.5
R
e
servoir mounting bracket to body nuts
4 -

5
R
e
servoir mounting bracket clamp
4 -

5
Fluid cooler to body2.
5 -
3.5
Transfer pipe
to steering rack7 -
8
Transfer pipe
to hydraulic con
trol valve
7 -

8

The fluid reservo
ir:
Is lo

cated in the engine compartment, mounted on the engine compartment fuse box bracket.
Incorporates

a 10 micron, li
fetime, integral filter.
Has a cap
acity of 0.4 liter.
Has a dipsti

ck incorporated into the filler cap for checking the fluid level.
A new reservoir must be fitted if the steering rack, pump or fluid cooler are renewed.
Fluid C
ooler

P
arts List
The fluid cooler:
Is
resiliently mounted on th
e front body cross member.
Coo
ls the fluid before it is
returned to the reservoir.
Is
of the wire-bound tube type.
Has i

ntegral hoses.
Supply and Return Hoses a

nd Pipework
The supply and return h
oses and
pipework deliver fluid at high pressure from the pump to th e steering rack assembly. The
fluid is then returned to th e reservoir through the cooler tube. The high pressure supply hose contains two cable-type
attenuators, one at each end, to reduce nois e. The return pipe is clipped to the steering rack housing by a resilient
mounting.
It
em
Par
t Number
De
scription
1—Fl

uid reservoir
2—Supply line
3—R

eturn line
4—Fi

ller cap
It

em
Par
t Number
De
scription
1—Front body cross member
2—F

luid cooler
3—Inte

gral hoses
4—Cooler m

ounting


P
arts List

Steering Column -
Torques



Comp

onent
Nm
Upper
steering column upp
er fixings
22
-
28
S
t
eering wheel to column securing bolt
34
-
46
Upper
bracket
to body screws
22
-
28
Upper
steering colu mn lower fi
xings
17
-
23
Lower steeri
ng col
umn pinch bolts (upper and lower)
28
-
34
U
pper
and lower cowl securing screws
1.
5 (
nominal)
D
river ai
r bag fixings
4 -
5
Colum
n switchgear to column
4 -
5

Speed an
d load
Coo
l
ant temperature
Ti
me el
apsed from start up
Cl
osed l
oop fuelling
Determination of the vapour concentration is made by stepped opening of the EVAP valve and subsequent monitoring of the
fuelling correction. This function is performed prior to purging, so that at the onse t of purging the EVAP valve can be set to
the optimum position. Should the ECM be unable to determine the concentration before purging, a default value is
employed, which is then modified whilst purging is in progress.
When the purging process is operational th e ECM modifies the basic fuelling calculation to maintain the correct air / fuel
ratio.
Purging is inhibited during fuel cut-off and stability / traction control intervention.
Coolant Temperature Sen
sor
Th
e
sensor outputs a voltage to the ECM which decreases as temperature increases.
Cooling Fans


In response to engi
ne coolant temperat
u
re and climate control system demand, the ECM will energize the cooling fans.
Climate Control Compressor
The E
C
M will allow the compressor clutch to be engaged if th
e engine temperature and load demand are normal. Should the
driver require maximum engine powe r or the coolant temperature be high, the request will be denied.
Cranking Signal

The ECM reacts to a signal fr
om th
e Body Processor Module (BPM) when the starter motor relay is energi
zed. This signal is
used to trigger starting, fu el and ignition strategies.
Engine Speed and Cranksh
aft Position
Engine
speed and cran
k position are moni
tored by a sensor which is mounted on the cylinder block (flywheel housing)
behind the crankshaft drive plat e. It indicates rotational speed to the ECM in the form of 12 pulses per crank revolution.
Engine speed is used for synchronization of fuel an d ignition systems, as well as other functions.
Camshaft Position
The ca
mshaft position sensor is mounted at
the rear of Bank 2 cylinder head on the inlet side and provides one signal every
720 degrees of crankshaft rotation. The signal, in conjunction with the signal from the crankshaft position sensor, indicates
to the ECM that the piston of cylinder 1A is approaching TDC on the compression stroke.
Variable Valve
Timing (Where Fitted)
By energi
si
ng a solenoid to allow the pass
age of pressurized oil on each of the inle t camshaft drives, the ECM can vary by a
single stepped amount, the relati ve timing of the inlet valves.
Ign
ition
Ignit
i
on spark is produced by
individual on-plug coil units.
There are two ignition amplifiers; module #1 drives coils 1A, 2B, 3B and 4A, whilst module #2 drives coils 1B, 2A, 3A and
4B. The ECM controls the amplifiers.