Jaguar XJ (X350). Manual — part 108

Ride Height Adjustments

Special Service Tools

Ride height gauge.

204-484

1. NOTE:

Fit special tool 204-484 as illustrated.

NOTE:

Make sure that the ride height gauge is vertical as shown.

Using the Jaguar approved diagnostic system carry out the ride height adjustments.

Description and operation

Vehicle Dynamic Suspension

Item

Part

Number

Description

1

—

Front vertical accelerometer

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2

—

Front air spring

3

—

Left-hand rear suspension height sensor

4

—

Left-hand front suspension height sensor

5

—

Right-hand front suspension height sensor (not used on vehicles built after

December 2003)

6

—

Right-hand rear suspension height sensor

7

—

Rear air spring

8

—

Solenoid valve block and air reservoir

9

—

Rear vertical accelerometer

10

—

Air suspension control module

11

—

Compressor

The vehicle dynamic suspension is a passive air suspension system providing vehicle levelling

independent of load. The system also improves the drag coefficiency by automatically lowering the

vehicle for high speed driving.

When driving at high speeds, the air suspension system will lower the vehicle to improve

aerodynamics and vehicle stability. The suspension will automatically return the vehicle to the

normal ride height when the vehicle slows.

NOTE:

Speed lowering is disabled when towing. Only Jaguar approved towing equipment will inhibit

this feature.

The air suspension system ensures that the vehicle is always at the correct ride height for varying

load conditions.

The air suspension system automatically adjusts the amount of air in the air springs to level the

vehicle. Air is supplied either from an air reservoir or a compressor. The compressor will run

periodically to fill the air reservoir.

The air suspension module (ASM) controls the operation of the solenoids in the valve block. The front

air springs are operated as a pair, the rear air springs are operated independently of each other. The

ASM adjusts one axle at a time, for example, when lifting the vehicle the rear axle is controlled first;

when lowering the vehicle the front axle is controlled first. This reduces headlamp glare during

leveling operations.

The ASM uses two different filter rates. When stationery, a 'fast' filter allows the system to react

quickly to payload changes. Whilst driving a 'slow' filter allows for compensation of the fuel level

change but does not react to road inputs for example pot holes and speed bumps.

Suspension Height Sensors

Vehicles built before December 2003 have four suspension height sensors which are mounted on the

front and rear subframe assemblies, two front and two rear. Vehicles built after December 2003 have

only three (the right front sensor being deleted), although the functionality of the system remains

the same. The suspension height sensors are linked to the suspension arms by drop link connections

and secured by means of a spring clip.

NOTE:

There may be some early vehicles which will have four sensors fitted, but which have the three-

sensor module, making the right front sensor redundant. To confirm the level of equipment,

read the module part number from the special applications menu in configuration on the Jaguar

approved diagnostic system. Part numbers before 'BJ' are four sensor, while 'BJ' and after are

three sensor. If the Jaguar approved diagnostic system is not available, remove the rear seat and

sound deadening and read the part number from the module.

NOTE:

Suspension height sensors require calibration if removed/refitted or replaced.

Air Springs

Two derivatives of the air spring are available, comfort and sport, the sport having slightly smaller

working volumes for higher spring rates.

The air springs are complemented by two versions of damper assembly, passive and active.

CAUTION: When removing and refitting the air spring and damper assemblies, care must be

taken to avoid damage to the internal seal assembly.

CAUTION: When working on the air spring and damper assembly, ensure that no twisting

occurs between the air spring top mounting and damper body. Twisting may result in damage to

the air spring inner components.

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