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and the safety belt buckle sensor. Based on this data, the RCM decides which level of airbag module deployment is required and forwards the information to the second area, the deployment handler.
The deployment handler evaluates the status of the seat track position sensor and safety belt buckle sensors before a decision
is made about which restraints should finally be deployed.
Data from the side crash sensors is used by the RCM in conjunction with acceleration data from the RCM internal accelerometer to make a deployment decision. The RCM processes the acceleration data and subject to an impact being of high enough severity, decides whether the side airbag module should be deployed.
On board testing of the airbag modules, front safety belt pretensioner firing circuits, warning indicator circuits and module
status (the crash and side impact sensors perform basic self-tests) is performed by the RCM together with the storing of fault codes.
The RCM drives the SRS indicator on the instrument pack via a CAN signal. If the warning lamp fails, a fault code is recorded and a warning tone is sounded in place of the lamp if a further fault occurs. It also provides a temporary back-up power supply
to operate the airbag modules in the event that in crash conditions, the battery supply is lost. In the event of a crash, it
records certain data which can be accessed via the diagnostic connector.
A safing sensor in the RCM provides confirmation of an impact to verify if airbag and pretensioner activation is necessary. A roll-over sensor monitors the lateral attitude of the vehicle. Various firing strategies are employed by the RCM to ensure that during an accident only the appropriate airbags and pretensioners are fired. The firing strategy used also depends on the
inputs from the safety belt switches and the occupant monitoring system.
An energy reserve in the RCM ensures there is always a minimum of 150 milliseconds of stored energy available if the power supply from the ignition switch is disrupted during a crash. The stored energy is sufficient to produce firing signals for the
driver airbag, the passenger airbag and the safety belt pretensioners.
When the ignition is switched on, the RCM performs a self-test and then performs cyclical monitoring of the system. If a fault is detected the RCM stores a related fault code and illuminates the airbag warning indicator. The faults can be retrieved by the recommended Jaguar diagnostic tool over the CAN bus. If a fault that could cause a false fire signal is detected, the RCM disables the respective firing circuit, and keeps it disabled during a crash event.
Clock Spring
The clockspring is installed on the steering column to provide the electrical interface between the fixed wiring harness of the
steering column and the components that rotate with the steering wheel, i.e. the driver airbag, the horn and the steering
wheel switch packs.
The clockspring consists of a plastic cassette which incorporates an outer cover fixed to the steering column and an inner rotor
which turns with the steering wheel. Four securing lugs attach the cover to the multifunction switch on the steering column.
The rotor is keyed to the steering wheel by a drive peg. A lug on the underside of the rotor operates the self-cancelling feature
of the turn signal indicator switch. A ribbon lead, threaded on rollers in the rotor, links two connectors on the cover to two
connectors on the rotor. Link leads for the driver airbag are installed in one of the connectors on the rotor.
To prevent damage to the ribbon lead, both the steering and the clockspring must be centralized when removing and installing
the clockspring or the steering wheel. The clockspring is centralized when the drive peg is at six o'clock and 50 - 100% of a
yellow wheel is visible in the viewing window.
Replacement clocksprings are fitted with a stopper, which locks the cover to the rotor, in the central position. The stopper must
be broken off when the replacement clockspring is installed.
Page 2629 of 3039

Supplemental Restraint System - Clockspring
Removal and Installation Published: 11-May-2011
Removal
WARNINGS:
Always wear safety glasses when repairing an air bag supplemental restraint system (SRS) vehicle and when handling an
air bag module.
Carry a live air bag module with the air bag and trim cover pointed away from your body. This will reduce the risk of injury
in the event of an accidental deployment. Failure to follow this instruction may result in personal injury.
Do not set a live air bag module down with the trim cover face down. Failure to follow this instruction may result in
personal injury.
After deployment, the air bag surface can contain deposits of sodium hydroxide, a product of the gas generant
combustion that is irritating to the skin. Wash your hands with soap and water afterwards. Failure to follow this instruction
may result in personal injury.
Never probe the connectors on the air bag module. Doing so may result in air bag deployment, which may result in
personal injury. Failure to follow this instruction may result in personal injury.
Air bag modules with discolored or damaged trim covers must be replaced, not repainted.
Vehicle sensor orientation is critical for correct system operation. If a vehicle equipped with an air bag supplemental
restraint system (SRS) is involved in a collision, inspect the sensor mounting bracket and wiring pigtail for deformation. If
damaged, replace the sensor whether or not the air bag is deployed.
To avoid accidental deployment and possible personal injury, the backup power supply must be depleted before repairing
or replacing any air bag supplemental restraint system (SRS) components. To deplete the backup power supply energy,
disconnect the battery ground cable and wait one minute. Failure to follow this instruction may result in personal injury.
CAUTION: Make sure the wheels are in the straight-ahead position. Failure to follow this instruction may result in
damage to the component.
NOTE: Removal steps in this procedure may contain installation details.
1. Make the SRS system safe.
Refer to: Standard Workshop Practices (100-00 General Information, Description and Operation).
2. CAUTIONS:
Make sure that special tool 211-326 is installed to the clockspring. 211-326
Locking Tool, Clockspring Special Tool(s)
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Make sure that the road wheels are in the straight ahead position,
failure to follow this instruction may result in damage to the vehicle.
Refer to: Steering Wheel (211-04 Steering Column, Removal and Installation).
3. CAUTION: Failing to install the special tool to the
clockspring may result in damage to the vehicle.
Special Tool(s): 211-326
4.
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8.
9.
10.
NOTE: Do not disassemble further if the component is
removed for access only.
Remove the special tool from the clockspring.
Special Tool(s): 211-326
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Installation
1. CAUTIONS:
Make sure that special tool 211-326 is installed to the
clockspring.
Make sure that the arrow on the cassette is centered
and pointing vertically (make sure that the steering wheel
has remained in the 12 o'clock position and that it has
not been turned by +/- 360 degrees) prior to the
steering wheel installation. On removal of the special tool,
keep the clockspring cables taught to prevent the cassette
moving from the set position. Failure to follow this
instruction may result in damage to the component.
Make sure that the road wheels are in the straight
ahead position, failure to follow this instruction may result
in damage to the vehicle.
To install, reverse the removal procedure.
Page 2653 of 3039
Supplemental Restraint System - Passenger Air Bag Module
Removal and Installation Published: 11-May-2011
Removal
NOTE: Removal steps in this procedure may contain installation details.
1. Refer to: Battery Disconnect and Connect (414-01 Battery, Mounting and Cables, General Procedures).
2. Refer to: Steering Wheel (211-04 Steering Column, Removal and Installation).
3. Refer to: Driver Side Register (412-01 Climate Control, Removal and Installation).
4. Refer to: Information and Entertainment Display (415-01A Information and Entertainment System, Removal and Installation).
5. Refer to: Instrument Panel Speaker (415-01A Information and Entertainment System, Removal and Installation).
6. Refer to: A-Pillar Trim Panel (501-05 Interior Trim and Ornamentation, Removal and Installation).
7. Refer to: Audio and Climate Control Assembly (415-01A Information and Entertainment System, Removal and Installation). 211-326
Locking Tool, Clockspring Special Tool(s)