Jaguar XJ (X350). Manual — part 86

Tread Wear Indicator

Tread wear indicators are molded into the bottom of the tread grooves across the width of the tire.

The tire must be renewed when tread wear indicators become visible at the surface of the tread, in

two or more adjacent tread grooves.

Note that tire tread depth and condition must comply with specific market legislations.

Tire Changing

Caution: When removing or installing a new tire care must be taken to make sure that the tire low

pressure sensor is not damaged. Make sure the tire bead is broken from the wheel rim 180 degrees

from the tire low pressure sensor. Failure to follow this instruction may cause damage to the tire low

pressure sensor.

Tire Pressure Monitoring

Visual Identification

Wheels fitted with the tire low pressure sensor can be visually identified by the external metal lock

nut and valve (1). All Jaguar non-tire pressure monitoring system wheels have a rubber valve fitted

(2).

The tire pressure monitoring system monitors pressure in each tire including the full size spare tire

(temporary-use spare wheels are not fitted with tire low pressure sensors and are consequently not

monitored).

Tire Pressure Monitoring System - Component Location

Item

Part Number

Description

1

Tire pressure monitoring system antenna

2

Tire low pressure sensor

3

Instrument cluster

4

External antenna

5

Tire pressure monitoring system module

The purpose of the tire pressure monitoring system is to assist the driver in maintaining the vehicle’s

tire pressures at the optimum level in order to:

•

improve fuel consumption

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•

maintain ride and handling characteristics

•

reduce the risk of rapid tire deflation – which may be caused by under inflated tires

•

comply with legislation in specific markets.

The tire pressure monitoring system measures the pressure in each of the tires on the vehicle and

issues warnings to the driver if any of the pressures deviate from a defined tolerance, which is

dependant on the vehicle market and the size and type of tire fitted.

Note: During a blow out a very rapid reduction in tire pressure is experienced. The system is not

intended to warn the driver of a blow out, since it is not possible to give the driver sufficient warning

that such an event is occurring, due to its short duration. The design of the tire pressure monitoring

system is to assist the driver in keeping the tires at the correct pressure, which may to reduce the

likelihood of a tire blow out occurring.

Tire Pressure Monitoring System Module

The tire pressure monitoring system module is located with the parking aid module in the luggage

compartment of the vehicle.

The tire pressure monitoring system module’s main function is to detect the following:

•

the tire pressure is below the recommended low tolerance value – under inflated tire

•

the position of the tire on the vehicle.

The tire pressure monitoring system module communicates with the vehicle instrument cluster to

provide the driver with appropriate warnings and also indicates the status/failure of tire pressure

monitoring system components.

Tire Location

Because of the requirement for different pressure targets and thresholds for the front and rear tires,

the tire pressure monitoring system module can identify the position of the tires on the vehicle, and

assign a received tire pressure sensor identification to a specific position on the vehicle (i.e. FL (front

left), FR (front right), RL (rear left) or RR (rear right)).

Tire location is performed automatically by the module using an auto-location function. This function

requires no manual intervention by the driver. The tire pressure monitoring system module can

automatically learn the position of tires on the vehicle if the tire pressure sensors or their positions

are changed on the vehicle.

The tire pressure monitoring system module can automatically detect, under normal conditions, the

following:

•

one or more tire pressure sensors have been replaced

•

one or more tire pressure sensor identifications are missing

•

one or more ‘alien’ identifications are being received, i.e. the module can reject
identifications from tire pressure sensors that do not belong to the vehicle

•

the spare tire and one of the tires in use on the vehicle have exchanged position on the
vehicle.

Spare Tire Identification

Depending on the vehicle specification, the spare tire may or may not be fitted with a tire pressure

sensor. Temporary-use spare wheels are not fitted with sensors and are consequently not

monitored.

If the spare tire is fitted with a tire pressure sensor, the tire pressure monitoring system module can

detect it, determine that it is the spare tire and monitor its pressure and issue warnings to the driver

accordingly. If the tire pressure monitoring system module does not detect a spare tire pressure

sensor, the tire pressure monitoring system module will not show a fault to the driver, however a

fault code will be stored in the tire pressure monitoring system module.

If the spare tire is being monitored and the driver replaces a flat road tire with the spare tire, the tire

pressure monitoring system module will not continually warn the driver that the original flat tire

(now in the spare position) is flat. This prevents distraction of the driver by constant pressure

warnings being issued. Warnings will only be displayed for 20 seconds after the ignition is switched

on.

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