2010 JAGUAR XFR ECU

Steering System - General Information - Steering System
Diagnosis and Testing

Principle of Operation Published: 11-May-2011

For a detailed description of the steering system operation, refer to the relevant Description and Operation sections of the
workshop manual. REFER to:

Power Steering (211-02 Power Steering, Description and Operation), Power Steering (211-02 Power Steering, Description and Operation), Power Steering (211-02 Power Steering, Description and Operation), Steering Linkage (211-03 Steering Linkage, Description and Operation), Steering Linkage (211-03 Steering Linkage, Description and Operation), Steering Linkage (211-03 Steering Linkage, Description and Operation), Steering Column (211-04 Steering Column, Description and Operation), Steering Column (211-04 Steering Column, Description and Operation), Steering Column (211-04 Steering Column, Description and Operation), Steering Column Switches (211-05 Steering Column Switches, Description and Operation), Steering Column Switches (211-05 Steering Column Switches, Description and Operation), Steering Column Switches (211-05 Steering Column Switches, Description and Operation).
Inspection and Verification

1. Verify the customer concern.

2. Visually inspect for obvious signs of damage and system integrity.

Visual Inspection
Mechanical Electrical
Tire condition/pressure
Fluid level
Leaks
Security, condition and correct installation of suspension components
Security, condition and correct installation of steering system components
Fuses
Harnesses for damage/corrosion
Electrical connector(s)
Damaged/corroded pins
CAUTION: If a steering gear assembly is returned under warranty with leaking output shaft 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 output
shaft seals being damaged due to foreign materials entering the steering gear boot and damaging the steering gear output
shaft seals thereafter.

3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to
the next step.
4. If the concern is not visually evident, verify the symptom and refer to the symptom chart.

Symptom Charts


WARNING: It is not possible to CHECK the torque of a patchlock bolt, if the torque is suspected to be low, the bolt must
be REMOVED/DISCARDED and a new bolt MUST be INSTALLED and torque to the correct value.


NOTE: If the module or a component is suspect and the vehicle remains under manufacturer warranty, refer to the
Warranty Policy and Procedures manual (section B1.2), or determine if any prior approval programme is in operation, prior to
the installation of a new module/component.

Fluid Leakage


NOTE: Confirm the location of the fluid leak. CLEAN the area of the leak, inspect the area and confirm the exact position.
Ensure the fluid is not from another system on the vehicle.

Symptom Possible Causes Action

Power steering
fluid leakage
Overfilled system
Correct the fluid level as required
Steering gear
Check and install new steering gear as required, refer to the new
module/component installation note at the top of the Symptom
Charts

5. CAUTION: Be prepared to collect escaping fluids.


NOTE: Make sure the extended pipe is not kinked or
twisted and is correctly secured with hose clips.

Attach a suitable pipe to the power steering return hose to
allow the fluid to drain.









6. NOTES:


The suitable funnel should have the a capacity of 4
litres and O-ring seal


The suitable funnel must be tightly sealed to the
power steering fluid reservoir to avoid fluid leakage.

Install a suitable funnel onto the power steering fluid
reservoir.












7. WARNING: Do not work on or under a vehicle supported only by a jack.
Always support the vehicle on safety stands.
Raise and support the vehicle with the wheels just clear of the ground.

8. CAUTIONS:


Steps 8 and 9 must be carried out within 2 - 3 seconds of each
other. Failure to follow this instruction may result in damage to the
power steering system.


Be prepared to collect escaping fluids.

Using the suitable funnel, top up the power steering system with the
specified fluid. Make sure the fluid level is maintained at two thirds full
in the funnel.

1 Locknut ( 2 off) 2 RH (right-hand) tie-rod 3 Steering gear boot (2 off) 4 Steering gear 5 Bolt and washer (3 off) 6 Servotronic valve 7 Valve unit 8 Input shaft 9 LH (left-hand) tie-rod 10 Steering gear mounting bushes The steering gear is located at the rear of the engine and attached to the front sub-frame. The gear is secured to the
sub-frame with 3 bolts and washers which screw into threaded tubes in bushes which are integral with the sub-frame.

The steering gear comprises an aluminum, cast, valve housing which contains the hydraulic valve unit and Servotronic valve.
The mechanical steering rack and the hydraulic actuator are located in a steel cylinder which is attached to the cast valve
housing.

The steering gear uses a rack with an integrated piston which is guided on plain bearings within the cylinder and the valve
housing. The pinion, which is attached to the valve unit, runs in bearings and meshes with the rack teeth. The rack is pressed
against the pinion by a spring loaded yoke which ensures that the teeth mesh with the minimum of play. The pinion is
connected to the valve unit via a torsion bar. The rotary motion of the steering wheel is converted into linear movement of the
rack by the rack and pinion mechanism and is initiated by the valve unit. This movement is transferred into movement of the
road wheels by adjustable tie-rods.

18 Pinion 19 Steering gear rack bar 20 Valve sleeve The valve unit is an integral part of the steering gear. The principle function of the valve unit is to provide power assistance
(i.e. when parking) to optimize the effort required to turn the steering wheel.

The pinion housing of the valve is an integral part of the main steering gear casting. The pinion housing has four machined
ports which provide connections for pressure feed from the power steering pump, return fluid to the reservoir and pressure
feeds to each side of the cylinder piston.

The valve unit comprises an outer sleeve, an input shaft, a torsion bar and a pinion shaft. The valve unit is co-axial with the
pinion shaft which is connected to the steering column via the input shaft. The valve unit components are located in the
steering gear pinion housing which is sealed with a cap.

The outer sleeve is located in the main bore of the pinion housing. Three annular grooves are machined on its outer diameter.
PTFE (polytetrafluoroethylene) rings are located between the grooves and seal against the bore of the pinion housing. Holes
are drilled radially in each annular groove through the wall of the sleeve. The bore of the outer sleeve is machined to accept
the input shaft. Six equally spaced slots are machined in the bore of the sleeve. The ends of the slots are closed and do not
continue to the end of the outer sleeve. The radial holes in the outer sleeve are drilled into each slot.

The input shaft has two machined flats at its outer end which allow for the attachment of the steering column intermediate
shaft yoke. The flats ensure that the intermediate shaft is fitted in the correct position. The inner end of the input shaft forms
a dog-tooth which mates with a slot in the pinion shaft. The fit of the dog-tooth in the slot allows a small amount of relative
rotation between the input shaft and the pinion shaft before the dog-tooth contacts the wall of the slot. This ensures that, if
the power assistance fails, the steering can be operated manually without over stressing the torsion bar. The central portion of
the input shaft has equally spaced longitudinal slots machined in its circumference. The slots are arranged alternately around
the input shaft.

The torsion bar is fitted inside the input shaft and is an interference fit in the pinion shaft. The torsion bar is connected to the
input shaft by a drive pin. The torsion bar is machined to a smaller diameter in its central section. The smaller diameter allows
the torsion bar to twist in response to torque applied from the steering wheel in relation to the grip of the tyres on the road
surface.

The pinion shaft has machined teeth on its central diameter which mate with teeth on the steering gear rack. A slot, machined
in the upper end of the pinion shaft mates with the dog-tooth on the input shaft. The pinion shaft locates in the pinion
housing and rotates on ball and roller bearings.

Servotronic Valve

The Servotronic transducer valve is located in a port in the side of the steering gear valve housing. The valve is sealed in the
housing with an O-ring seal and is secured with two long screws into threaded holes in the housing. The Servotronic valve is a
transducer controlled valve which responds to control signals supplied from Servotronic software in the instrument cluster.

The Servotronic valve determines the hydraulic reaction at the steering gear rotary valve and controls the input torque required
to turn the steering wheel. The Servotronic system allows the steering to be turned with the optimum effort when the vehicle
is stationary or manoeuvred at slow speed. The hydraulic reaction changes proportional to the vehicle speed, with the required
steering effort increasing as the vehicle moves faster. At high speeds, the Servotronic system provides the driver with a good
feedback through the steering providing precise steering and improved stability.

The instrument cluster receives road speed signals from the ABS module and calculates the correct controlling signal for the Servotronic valve. The Servotronic software within the instrument cluster has a diagnostic capability which allows a Jaguar
approved diagnostic system to check the tune of the steering and retrieve fault codes relating to the Servotronic valve. Two
fault codes are stored relating to the valve for positive connection short to ground or battery and negative connection short to
ground or battery.

The Servotronic software within the instrument cluster also contains a number of steering maps which are selected via the car
configuration file depending on the vehicle model and tire fitment.

If a failure of the Servotronic valve or software occurs, the system will suspend Servotronic assistance and only a default level
of assistance will be available. Fault codes relating to the fault are stored in the instrument cluster. No warning lamps are
illuminated and the driver may be aware of the steering being 'heavier' than usual.
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Published: 11-May-2011
Steering Linkage - Steering Linkage - System Operation and Component Description
Description and Operation


TIE-ROD System Operation

The threads on the tie rods allow the position of the outer tie rod to be adjusted in order to set the correct toe angle for each
front wheel.


TIE-ROD Component Description

Each tie rod comprises two parts; an inner and outer tie rod. The inner and outer tie rods are screwed into each other and
locked with a locknut to prevent inadvertent movement.

The outer tie rod incorporates a non-serviceable tapered ball joint which locates in a tapered hole in the front wheel knuckle
and is secured with a self-locking nut. The ball joint has an internal hexagonal drive which enables the joint to be held
stationary when the self-locking nut is tightened.

STEERING COLUMN Component Description



Item Description 1 Rake housing 2 Electric steering column lock 3 Mounting plate 4 Rake lever 5 Crash tube 6 Distance keeper 7 Steering wheel mounting splines 8 Steering angle sensor ring 9 Crash adaptor 10 Rake lever pivot bearing (2 off) 11 Flanged locknut (4 off) - mounting to cross-beam 12 Rake solenoid 13 Rake clutch 14 Spindle 15 Reach solenoid 16 Reach clutch 17 Column adjustment motor 18 Outer clamping yoke 19 Clamp bolt 20 Inner tube yoke
WARNING: Do not attempt to dismantle the steering column. The crash safety of the unit will be compromised.

The steering column is attached to the in-vehicle cross-beam and secured with 4 flanged lock nuts onto 4 studs integral with
the cross-beam.

16 Ball (12 off) 17 Distance keeper 18 Crash tube The column comprises a cast magnesium mounting bracket which provides the attachment to the cross-beam. Attached to the
mounting bracket is a rake lever which is attached to the mounting bracket at the lower end with two pivot bearings. The
bearings allow the rake lever to rotate upwards or downward to adjust the column rake.

The rake lever also provides for the attachment of the rake housing which can slide within the lever to provide the reach
adjustment. Within the rake housing is the axial housing which is supported on each side with 6 ball bearings which allow the
rake housing to move forward or backwards. The bearings on each side are arranged in groups of 3 bearings and are separated
by a distance keeper which allows the housing to supported on bearings along its length. Within the axial housing is a tube
which is supported at the upper end of the column on the upper bearing. The tube has a central splined hole which provides for
the fitment of the splined shaft. The splined shaft can slide within the tube on the splines when the column reach is adjusted
or the column collapses in a crash condition. The splined shaft also passes rotary motion from the steering wheel through the
length of the column to the outer clamping yoke which is supported on the lower bearing.

The electric steering column lock is attached to the top of the rake lever. A lock bolt within the steering column lock engages in
one of 8 slots in the locking sleeve located at the lower end of the column preventing rotation of the steering wheel. The
locking sleeve is retained by a tolerance ring which in turn is located on the outer diameter of the tube yoke. The tolerance
ring allows a specified amount of torque to be applied to the splined shaft before it slips, preventing damage to the column
lock due to excessive force being applied to the steering wheel when the lock is engaged. The tolerance ring is designed to
slip on the splined shaft when the applied torque exceeds the fitted slip load of 200 Nm minimum. Repeated rotation of the
lock collar will reduce its slipping torque to 100 Nm minimum. The lock is controlled by the CJB.
A steering angle sensor is located at the upper end of the steering column and is attached to the crash adaptor. The sensor
measures steering rotation via a toothed wheel located on the splined tube at the upper end of the column. The sensor
receives a power supply from the CJB and supplies 2 signals (A and B) relating to the steering rotation to the ABS (anti-lock brake system) module. The module transmits this data on the high speed CAN bus for use by other vehicle systems. Refer to: Anti-Lock Control - Stability Assist (206-09 Anti-Lock Control - Stability Assist, Description and Operation).
The steering column is adjustable electrically, for reach and rake. The adjustment mechanism comprises an electric adjustment
motor, a lead screw, a rake solenoid, a reach solenoid, a reach clutch and a rake clutch. The column adjustment is controlled
manually using a joystick switch located on the LH (left-hand) side of the column lower cowl. The joystick can be moved
forward and backward to adjust the column reach in and out and moved up and down to adjust the rake. The switch selection
energizes the adjustment motor in the applicable direction and also engages the applicable solenoid and clutch.

When the joystick switch is rotated to the 'auto' position, the steering column will adjust to the uppermost rake position when
the ignition is switched off. It will re-adjust to the position corresponding to the memory position for the remote handset when
the ignition is switched on.

The memory function of the electric column is linked to and controlled by the driver's seat module. The module provides for the
storage of three separate memory positions which are stored against 3 individual remote handsets.
Refer to: Seats (501-10 Seating, Description and Operation).
The steering wheel locates on a splined shaft in the upper column assembly and is secured with a bolt. The steering wheel
houses the driver's airbag and switches for the audio system, gear change and speed control. A clockspring is used to connect
the steering wheel electrical components to the vehicle harness.

Two plastic shrouds are fitted to the upper column assembly. The lower shroud is fitted with an energy absorbing foam pad to
minimize leg injury in the event of an accident.
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1 Yoke 2 Upper collapse shaft 3 Flexible coupling 4 Shaft plate 5 Rivet (4 off) 6 Upper tube 7 Plastic sleeve 8 Boot 9 Bearing (4 off) 10 Teeth tube 11 Lower shaft 12 Yoke clamp bolt (2 off) 13 Bearing (4 off) 14 Lower yoke 15 Spider 16 Upper yoke The lower shaft assembly comprises 2 splined shafts connected by a universal joint in the center.

The upper collapse shaft has a flexible couple at its upper end. The flexible coupling controls axial and torsional movements
and also assists with noise and vibration damping. The flexible coupling is fitted with a shaft plate which has a boss with
machined flats on it. The flats provide positive location on the upper column outer clamping yoke. A cut-out in the boss allows
for the fitment of a clamping bolt to secure the upper column outer clamping yoke. The cut-out ensures that the lower shaft
assembly can only be fitted in one orientation.

The upper collapse shaft is connected to the stopper plate of the flexible coupling with splines. The stopper plate is connected
to the shaft plate via the flexible coupling and is secured with rivets. The upper collapse shaft has a series of splines which
engage with the upper tube. The splines allow the upper collapse shaft to slide into the upper tube in the event of an
accident.

The upper tube is positively connected to the upper half of the yoke of the universal joint. A plastic tube is located around the
upper tube and provides for the attachment of a boot which seals the lower shaft assembly where it passes through the
vehicle bulkhead. LOWER SHAFT ASSEMBLY