Page 489 of 2490

modul
e. This regulates the fluid flow
through the hydraulic control valve, wh ich determines the amount of steering
assistance.
Steering Control Module
The steering control
module re
ceives the vehicle speed from the instrument cluster and outputs the corresponding current
values to the Servot ronic valve. At parking speeds, wh en maximum assistance is required , the current is at its maximum
value of 854 mA and the valve is closed. As the vehicle speed increases, the current progressively decreases to its minimum
value of 15 mA and the valve opens in sma ll increments. This results in an increasing amount of hydraulic pressure being
applied to the reaction piston, making the steering feel more precise and responsive.
The rate of progression and shape of the characteristic between parking and high speed operation, is determined by the
algorithm within the steering control module, and is matched to each suspension variant within the vehicle range.
Control Module Connections
It
em
De
scription
1Servotronic valve
2Steeri
ng control module
3No
t used
4Vehi
cle speed input
5Ground
6Ignition su
pply +12V
7Base of
steering control module
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Power Steering - Power Steering
Diagn
osis and Testing
Refer to the Description and Operation sub-section for details of the power operated steering system and Servotronic control
system.
Power Steer ing Pressure Test
Test Equ
i
pment
Parts List
In
stalling Test Equipment
To
in
stall the pressure test equipment:
Pla
c
e a suitable drain tray below the PAS pump.
Install a hose clamp
on
the re
servoir to pump hose prior to disconnecting any hoses, to avoid unnecessary loss of
fluid.
Di sc
onnect the hose from the PAS pump high pres
sure outlet.
Ins
tall the pump outlet to hose ad
aptor. Do not omit the O-ring.
Conn
ect the pump adaptor to control valve hose of the test equipment.
Install th
e adaptor in the high pressure hose previ
ously re
moved from the pump outlet.
Conne
ct the connector of the test equipment hose to the adaptor.
R
e
move the hose clamp fro
m the reservoir hose.
Start th
e engine.
With the control valve OPEN and the engine idling , the following system pressures may be checked:
Du
ring turning.
W
h
en the steering is
held on full lock.
With
the steeri
ng at rest.
• WARNINGS:
TO AVOID EXCESSIVE HEATING OF THE PAS PUMP, DO NOT CLOSE THE VALVE FOR LONGER THAN NECESSARY.
Ite
m
Par
t
Number
De
scr
iption
1—Pressure
gauge hose
2—Pump return hose
3—Pump return hose connector
4—Test equi
pment to
HP hose adaptor
5—Pump HP outlet to hose adaptor
6—Pump adaptor
to control valve hose
7—Control valve
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DO NOT DRIVE THE VEHICLE WITH THE TEST EQUIPMENT INSTALLED.
With the control valve CLOSED the pump maximum output pressure can be checked.
Remov
ing Test Equipment
T
o remove the test equipment:
Install a hose clamp
on the
reservoir to pump hose.
Re
moving the test equipmen
t is a reversal of the installation instructions.
Install a new O-r
ing to the PAS pump high
pressure outlet to hose connection.
Inst
all the original hose to the PAS pump.
R
emove the clamp from the reservoir to pump hose.
Top-up the reservoi
r fluid.
B
leed the PAS system; refe
r to this section.
Refer to PDU
User Guide
T
he PDU will diagnose all electrical components of the system.
Before changing a component, chec k fuse No. 12 (10A) in the left-hand heelboard fu se box. However, if this fuse is faulty a
number of other components wi ll also fail to function.
Page 492 of 2490
Power Steering - Steering Gear
Remo
val and Installation
Remov
a
l
All vehicles
S
p
ecial Tool(s)
Taper Sep
a
rator
211-098 (JD 100)
1. Centralize steeri ng the wheel.
2. Raise and support the vehicle on a four-post ramp.
3. Place a suitable drain pan under the stee ring gear.
4. Fr
om below the vehicle, check that
steering gear is centralized
by aligning the centralizing notc h on the dirt protection cover
with the location hole in the pinion housing casting.
5. NOTE : R
ight-hand shown, left-hand similar.
Remove and discard bo th tie rod end nuts.
6. NOTE : R
ight-hand shown, left-hand similar.
Detach both of the tie rod ends.
1. Fit the special tool to tie rod end.
2. Tighten the tool bolt to release the taper.
Re
move the tool.
Page 493 of 2490
Righ
t-hand drive vehicles
All vehicles
7. De
tach the steering
column lower shaft.
1. Loosen the steering column lower shaft retaining bolt.
2. Remove and discard the st eering column lower shaft
retaining bolt.
3. Detach the steering column lower shaft.
8. Di
sconnect the steering gear transducer electrical connector.
9. Cut an
d discard the stee
ring gear transducer harness tie-strap.
10
.
Cut and discard the power steeri ng return pipe tie-strap.
11. Detach the power steering re turn pipe from the mounting
rubber.
Page 494 of 2490

In
stallation
All vehicles
Route t
he steering gear transducer harness from behind
the power steering return pipe (right-hand drive vehicles
only).
12 . Remove the
power steering supply and return pipe retaining
plate bolt and with draw the plate.
13 . D
rain the power steering fluid.
Di
sc
onnect the power steering
supply and return pipes and
allow the fluid to drain.
Remove an d discard the ´O´ring seals from the
pipe
connectors.
Fi t su
itable blanking caps
to the pipe connectors and
pinion housing ports.
14. Remove the drain pan and discard the fluid.
15. NOTE: The steering gear mounting bushings are handed;
they are marked accordingly and must be replaced as a pair.
Remove the steering gear mo unting bracket bushings.
For additional information, refer to: Steering Gear Bushing
( 21
1-02 Power Steering, Removal and Installation).
16. NOTE: When removing the steering gear, manoeuvre the
power steering return pipe past the pinion housing to steering
gear pipes.
Remove the steering gear.
17. Using a tap (M10 x 1.5 mm), clean the steering gear to
crossbeam bolt hole threads.
1. If a new steering gear assembly is to be fitted, make sure
steering gear is centrali zed before installation.
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2. NOTE
: When installing the steering gear, manoeuvre the power
steering return pipe past the pinion housin g to steering gear
pipes.
• NOTE: A new steering gear assembly is supplied with a dirt
protection cover/cent ralizing cap fitted.
Position the steering gear to vehicle.
3. Install the steering gear mo unting bracket bushings.
For additional information, refer to: Steering Gear Bushing
(
211-02 Power Steering, Removal and Installation).
4. Conne
ct the power steering su
pply and return pipes to the
pinion housing.
R
emove the blanking caps an
d install new ´O´ring seals in
pipe connectors.
lubri
cate the ´O´ring seals wi
th clean power steering fluid.
R
emove the blanking caps from
the pinion housing ports.
Position the power
steering su
pply and return pipes to the
pinion ports and seat ´O´rings.
5. Attach
the power steering supply
and return pipes to the pinion
housing.
Ensure the power steering su pply
and return pipes and the
retaining plate are correctly seated.
Install th
e bolt.
Tigh
ten to 9-12 Nm.
6. Clean any fluid spillage from the steering gear and surrounding
area.
7. Attach the power steering return pipe to the steering gear.
Attach
the rubber support to
the power steering return
pipe.
Rout
e the steering gear transducer harness behind the
power steering return pipe (right-hand drive vehicles
Page 496 of 2490
Right
-hand drive vehicles
All vehicles
only
).
8. Install a new power st ee
ring return
pipe tie-strap.
9. Install a new steering gear transducer harness tie-strap.
10 . Conne
ct the steering gear transducer electrical connector.
On righ
t-hand drive vehicles
, position the steering gear
transducer harness behind th e power steering return pipe.
11
. NOTE
: Right-hand shown, left-hand similar.
Attach the tie rod end.