each damper to the appropriate level to maintain a flat and level body.
Roll Rate Control – Uses CAN inputs. Predicts vehicle roll rate due to driver steering inputs 100 times a second and increases damping to reduce roll rate.
Pitch Rate Control – Uses CAN inputs. Predicts vehicle pitch rate due to driver throttle and braking inputs 100 times a second and increases damping to reduce pitch rate.
Bump Rebound Control – Uses suspension height sensor and CAN inputs. Monitors the position of the wheel 500 times a second and increases the damping rate as the damper approaches the end of its travel.
Wheel Hop Control – Uses suspension height sensor and CAN inputs. Monitors the position of the wheel 500 times a second and detects when the wheel is at its natural frequency and increases the dampingto reduce vertical wheel
motion.
Under normal road conditions when the vehicle is stationary with the engine running, the dampers are set to the firm condition
to reduce power consumption.
The adaptive damping module receives its power supply via a relay and fuse in the CJB. The relay remains energized for a period of time after the ignition is off. This allows the adaptive damping module to record and store any DTC (diagnostic
trouble code) relating to adaptive dynamics system faults.
DAMPERS Component Description
Item Description A Front spring and damper assembly B Rear spring and damper assembly The 'Adaptive Dynamics' dampers are monotube, nitrogen gas and oil filled units, manufactured by Bilstein. The dampers are
continuously variable, which allows the damping force to be electrically adjusted when the vehicle is being driven. The variable
dampers provide the optimum compromise between vehicle control and ride comfort.
The dampers have an electrical connector on the end of the piston rod, in the center of the top mount (the dampers look
identical to those on the Computer Active Technology Suspension (CATS) system of 4.2L supercharged vehicles, but have a
different part number).
In each damper, the continuous damping adjustment is achieved by a solenoid operated variable orifice, which opens up an
alternative path for oil flow within the damper. When de-energized the bypass is closed and all the oil flows through the main
(firm) piston. When energized, the solenoid moves an armature and control blade, which work against a spring. The control
blade incorporates an orifice which slides inside a sintered housing to open up the bypass as required. In compression, oil
flows from the lower portion of the damper through a hollow piston rod, a separate soft (comfort) valve, the slider housing and
orifice and into the upper portion of the damper, thereby bypassing the main (firm) valve. In rebound the oil flows in the www.JagDocs.com
Brake System - General Information - Brake System
Diagnosis and Testing
Principle of Operation Published: 11-May-2011
For a detailed description of the brake system, refer to the relevant Description and Operation sections in the workshop
manual. REFER to:
Front Disc Brake (206-03, Description and Operation),
Front Disc Brake (206-03, Description and Operation),
Front Disc Brake (206-03, Description and Operation),
Rear Disc Brake (206-04, Description and Operation),
Rear Disc Brake (206-04, Description and Operation),
Rear Disc Brake (206-04, Description and Operation),
Parking Brake (206-05 Parking Brake and Actuation, Description and Operation), Parking Brake (206-05 Parking Brake and Actuation, Description and Operation), Parking Brake (206-05 Parking Brake and Actuation, Description and Operation), Hydraulic Brake Actuation (206-06 Hydraulic Brake Actuation, Description and Operation), Hydraulic Brake Actuation (206-06 Hydraulic Brake Actuation, Description and Operation), Hydraulic Brake Actuation (206-06 Hydraulic Brake Actuation, Description and Operation), Brake Booster (206-07 Power Brake Actuation, Description and Operation), Brake Booster (206-07 Power Brake Actuation, Description and Operation), Brake Booster (206-07, Description and Operation).
Inspection and Verification
Visually examine the front and rear wheel and tire assemblies for damage such as uneven wear patterns, tread worn out or
sidewall damage. Verify the tires are the same size, type and, where possible, same manufacturer. Replace the damaged
wheel or excessively worn tire.
Wheels and tires must be cleared of any foreign matter and tire pressures adjusted 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 necessary, check and adjust front wheel alignment. REFER to: (204-00 Suspension System - General
Information)
Specifications (Specifications), Front Toe Adjustment (General Procedures).
Visual Inspection
Mechanical Electrical
Brake master cylinder
Brake caliper piston(s)
Brake discs
Wheel bearings
Brake pads
Power brake booster
Brake pedal linkage
Brake booster vacuum hose
Tires
Debris
Parking brake actuator
Parking brake module
Parking brake switch
Damaged or corroded wiring harness
Brake master cylinder fluid level switch Road Test
Carry 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 comparisons 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 detect performance concerns.
An experienced brake technician will always establish a route that will be used for all brake diagnosis road tests. The roads
selected will be reasonably smooth and level. Gravel or bumpy roads are not suitable because the surface does not allow the
tires to grip the road equally. Crowned roads should be avoided because of the large amount of weight shifted to the low set
of wheels on this type of road. Once the 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 suspected condition. From the description, the
technician's experience will allow the technician to match possible causes with symptoms. Certain components will be tagged
as possible suspects while others will be eliminated by the evidence. More importantly, the customer description can reveal
unsafe conditions which should be checked 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 light and heavy pedal pressure. To determine if the concern is in the front or rear braking
system, use the brake pedal and then use the parking brake control. If the condition (pull, vibration, pulsation) occurs only
with the parking brake, the concern is in the rear brake system.
If the concern becomes evident during this check, verify it fits the description given before the road test. If the concern is not
evident, attempt to duplicate the condition using the information from the description.
If a concern exists, use the Symptom Chart in order to isolate it to a specific sub-system and condition description. From this
description, a list of possible sources can be used to further narrow the cause to a specific component or condition.
Symptom Chart
Symptom Possible Cause Action Brakes noisy
Brake pads
Brake discs GO to Pinpoint Test A. Vibration when brakes are
applied
Wheels/tires out of balance
Wheel hub nuts loose
Brake caliper mounting bolts loose
Brake pads
Foreign material/scratches/corrosion
on brake disc contact surfaces
Excessive brake disc thickness
variation
Excessive brake disc runout
Wheel bearing wear or failure
Suspension bushing wear or failure
Steering bushing wear or failure GO to Pinpoint Test B. The brakes pull or drift
Tire pressures/wear
Brake calipers
Brake pads
Brake discs
Wheel alignment adjustment
Wheel bearing
Suspension bushings and ball joints GO to Pinpoint Test C. The pedal feels spongy
Air in brake hydraulic system
Leak in hydraulic system
Brake booster/master cylinder
Brake pads GO to Pinpoint Test D. The pedal goes down fast
Air in brake hydraulic system
Leak in hydraulic system
Brake booster/master cylinder
Brake pads GO to Pinpoint Test E. The pedal goes down
slowly
Air in brake hydraulic system
Brake booster/master cylinder GO to Pinpoint Test F. Excessive brake pedal
effort required
Brake pads
Brake booster GO to Pinpoint Test G. Brake lockup during light
brake pedal force
Brake pads
Brake calipers GO to Pinpoint Test H. Brakes drag
Parking brake control
applied/malfunction
Seized parking brake cables
Seized brake caliper slide pins
Seized brake caliper
Brake booster
Pedal gear GO to Pinpoint Test I. Excessive/Erratic brake
pedal travel
Hydraulic system
Brake pads Brake
discs
Hub and bearing assembly GO to Pinpoint Test J. The red brake warning
indicator is always on
Fluid level
Brake master cylinder fluid level
sensor
Parking brake control Fill the system to specification. Check for leaks.
Install a new brake master cylinder fluid reservoir as
required.
REFER to: Brake Fluid Reservoir (206-06 Hydraulic Brake Actuation, Removal and Installation).
7 Brake fluid level switch 8 LH rear wheel speed sensor 9 RH rear wheel speed sensor 10 RJB (rear junction box) 11 High mounted stop lamp 12 LH stop lamp 13 RH stop lamp 14 Diagnostic socket 15 TCM (transmission control module) 16 Electronic parking brake module 17 ECM (engine control module) 18 Instrument cluster 19 ABS (anti-lock brake system) module 20 JaguarDrive selector module 21 Adaptive damping control module 22 Adaptive speed control module 23 Yaw rate and lateral acceleration sensor 24 Roof opening panel motor/module 25 Brake booster vacuum sensor (3.0L vehicles only) 26 Steering angle sensor
Anti-Lock Brake System System Operation
ABS controls the speed of all road wheels to ensure optimum wheel slip when braking at the adhesion limit. The wheels are prevented from locking to retain effective steering control of the vehicle.
The brake pressures are modulated separately for each wheel. Rear brake pressures are controlled to maintain rear stability on
split friction surfaces.
Dynamic Stability Control
DSC (dynamic stability control) uses brakes and powertrain torque control to assist in maintaining the yaw stability of the
vehicle. While the ignition is energized the DSC function is permanently enabled, unless selected off using the DSC switch.
DSC enhances driving safety in abrupt maneuvers and in under-steer or over-steer situations that may occur in a bend. The
ABS module monitors the yaw rate and lateral acceleration of the vehicle, steering input and individual wheel speeds, then selectively applies individual brakes and signals for powertrain torque adjustments to reduce under-steer or over-steer
conditions.
In general:
In an under-steer situation the inner wheels are braked to counteract the yaw movement towards the outer edge of the
bend.
In an over-steer situation the outer wheels are braked to prevent the rear end of the vehicle from pushing towards the
outer edge of the bend.
The ABS module monitors the tracking stability of the vehicle using inputs from the wheel speed sensors, the steering angle sensor, and the yaw rate and lateral acceleration sensor. The tracking stability is compared with stored target data. Whenever
the tracking stability deviates from the target data, the ABS module intervenes by applying the appropriate control strategy. The following interactions occur in an intervention situation:
High speed CAN signal to the ECM, to reduce engine torque. Application of braking to the appropriate corner of the vehicle.
Trac DSC
TracDSC is an alternative setting of DSC with reduced system interventions. With TracDSC engaged, traction may be somewhat
increased, although stability may be reduced compared to normal DSC. TracDSC is intended for use only on dry tarmac, by
suitably experienced drivers and should not be selected for other surfaces or by drivers with insufficient skill and training to
operate the vehicle safely with the TracDSC function engaged.
The less restrictive TracDSC setting may be preferred, for example, by expert drivers engaged in high performance driving on
dry Tarmac surfaces such as tracks and circuits.
Switching between DSC and Trac DSC:
Symptom Possible Causes Action Suspension System - General
Information)
Camber and Caster Adjustment (General Procedures),
Front Toe Adjustment (General Procedures),
Rear Toe Adjustment (General Procedures).
Vehicle is unevenly loaded or overloaded
Notify the customer of incorrect
vehicle loading
Steering gear is not correctly adjusted
CAUTION: DO NOT attempt to
adjust the steering gear yoke. Failure to
follow this instruction will invalidate the
steering gear warranty
Check and install a new steering
gear as required, refer to the
new module/component
installation note at the top of
the Symptom Charts
Loose, damaged or worn front suspension
components
Check/tighten and install new
front suspension components as
required.
REFER to: Specifications (204-00 Suspension System - General
Information, Specifications).
Loose, damaged or worn rear suspension
components
Check/tighten and install new
rear suspension components as
required.
REFER to: Specifications (204-00 Suspension System - General
Information, Specifications).
Incorrect brake operation
For information on diagnosis of
the brake system.
REFER to: Brake System (206-00 Brake System - General
Information, Diagnosis and
Testing).
Incorrect underbody alignment
Set underbody alignment
referring to the Removal and
Installation procedures in section
502-00 of the workshop manual
for instruction
Vehicle wanders from
side to side when driven
straight ahead and the
steering wheel is held in
a firm position
Incorrect tire pressure or tire size
Check and adjust the tire
pressures as required.
REFER to: Specifications (204-04 Wheels and Tires,
Specifications).
Check and install a new tire as
required
Vehicle is unevenly or excessively loaded
Notify the customer of incorrect
vehicle loading
Incorrect toe adjustment
Check and adjust as required.
REFER to: (204-00 Suspension
System - General Information)
Camber and Caster Adjustment (General Procedures),
Front Toe Adjustment (General Procedures),
Rear Toe Adjustment (General Procedures).
Symptom Possible Causes Action
Knock
Loose fixings (universal joint
pinch bolt and steering column
fixings)
Tighten fixings to correct specification.
REFER to: Specifications (211-00 Steering System - General Information, Specifications).
Rattle
Foreign objects
Remove foreign objects from between steering
column shroud and steering wheel/steering
column rotating components
Loose fixings
Tighten steering column fixings to correct
specification.
REFER to: Specifications (211-00 Steering System - General Information, Specifications).
Noise while adjusting
column
Electric motor/solenoid
NOTE: Before carrying out repairs/replacement,
assess column adjustment noise levels against other
vehicles of the same model
Install new components as required
Motor spindle/lead screw
Lubricate lead screw Vibration
Symptom Possible Causes Action
Wheel Fight (Kick Back) - condition
where roughness is felt in the
steering wheel by the driver when
the vehicle is driven over rough
surfaces
Loose or worn steering
components/bushings
CAUTION: DO NOT attempt to adjust the
steering gear yoke. Failure to follow this
instruction will invalidate the steering gear
warranty.
Tighten and install new steering
components/bushings as required
Loose or worn suspension
components/bushings
Tighten and install new suspension
components/bushings as required
Nibble (Shimmy) - condition where
oscillation of the steering wheel
occurs (not vertical which is Shake).
This is driven by road wheel
imbalance
Road wheel and tire
condition
Check for wheel and tire damage. Install
new components as required
Check for tire uniformity. Install new
tire(s) as required
Road wheel imbalance
Check and adjust road wheel balance as
required
Shake - condition where vertical
vibration of the steering
wheel/column occurs (not
oscillation which is Nibble)
NOTE: Vibration smooths out
after several miles of driving
Road wheel imbalance due
to tire flat-spotting
Ensure tires installed are to Jaguar
specification. Install new tires as
required
Check and adjust tire pressures to
correct specification Component Tests
Steering Linkage Inspection and Backlash (Free play) Check
CAUTION: Steering gear boots must be handled carefully to avoid damage. Use new clamps when installing steering gear
boots.
Inspect the boots for cuts, deterioration, twisting or distortion. Check the steering gear boots to make sure they are tight.
Install new boots or clamps as required.
NOTE: The following steps must be carried out with assistance.
1. With the wheels in the straight ahead position, gently turn the steering wheel to the left and the right to check for free
play.
1 Steering wheel 2 Gear change paddle switch 3 Column adjust switch 4 Lower shroud 5 Rake adjustment housing 6 Reach adjustment housing 7 Column adjustment motor 8 Lower column - Upper collapse shaft 9 Bulkhead bearing and seal assembly 10 Lower column - Lower collapse shaft 11 Electric steering lock mechanism 12 Column mounting plate 13 Upper shroud
Steering Column - Steering Column - Overview
Description and Operation
OVERVIEW Published: 11-May-2011
The steering column comprises the upper column assembly, the lower column assembly and the steering wheel. The 3
components are positively connected together to pass driver rotary input from the steering wheel to a linear output of the
steering rack.
The upper column assembly contains electrical adjustment for steering wheel reach and rake, the electric steering lock
mechanism and the steering angle sensor. Steering adjustment memory positions are stored in the driver's seat module.
The electric steering column is a standard fitment on all models. The upper column assembly contains electrical adjustment for
steering wheel reach and rake, the electric column lock mechanism and the steering angle sensor. Steering adjustment memory
positions are stored in the driver's seat module. The column also features a 'tilt away' function which moves the steering
column away from the driver allowing easier exit and entry to the vehicle.
Column adjustment is provided by a single motor for both reach and rake adjustment. Operation of the column adjustment is
controlled by a four way joystick type switch located in the column lower shroud. Column adjustment is an integral part of the
driver position memory system.
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