2010 JAGUAR XFR turn signal

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.

position sensor consists of a Hall effect sensor attached to the driver seat frame. While the ignition is on, the RCM supplies the sensor with power, and monitors the return current. When the seat frame moves forwards, the sensor moves over the edge
of the seat track, which changes the reluctance of the sensor. The change of current is detected by the RCM and used as a switching point. The switching point is when the center of the sensor is 3 ± 4 mm from the leading edge of the seat track.

When the driver seat is forward of the switching point, the RCM increases the time delay between firing the two stages of the inflator in the driver airbag. When the driver seat is rearward of the switching point, the RCM uses the normal time delay between firing the two stages.

Safety Belt Sensor

A safety belt switch is installed in the buckle of each front safety belt to provide the RCM with a status signal of the related safety belt(s). When the safety belt is unfastened the switch outputs a low current to the RCM. When the safety belt is fastened the switch outputs a high current to the RCM.
Pretensioners



Item Description 1 Front seat safety belt switch 2 Front seat safety belt pretensioner 3 Electrical connector The pretensioners are used to tighten the front safety belts during a collision to ensure the occupants are securely held in
their seats. A pretensioner is integrated into each front safety belt buckle and attached to a bracket on the inboard side of the
seat.

Each pretensioner has a tube containing propellant and a piston. The piston is attached to a steel cable, the opposite end of
which is attached to the safety belt buckle. A squib in the base of the tube provides an ignition source when triggered by a fire
signal from the RCM.
On receipt of a fire signal from the RCM, the squib ignites the propellant. The propellant produces nitrogen gas that rapidly expands to drive the piston along the tube, pulling the cable and drawing the buckle downwards.

7 RH accelerometer 8 LH accelerometer 9 RJB (rear junction box) 10 BJB (battery junction box)
System Operation
The pedestrian protection system is operational when the vehicle is traveling at speeds between approximately 20 km/h (12.4
mph) and 45 km/h (28 mph). A vehicle speed signal is received by the pedestrian protection system control module over the
high speed CAN bus.
The system is able to determine if contact is made with a pedestrian or another object, such as a traffic cone, using signals
from accelerometers mounted behind the front bumper. When the system determines contact is made with a pedestrian it fires
the actuators to lift the rear of the hood approximately 130 mm within 35 ms of the 'fire' signal.

When an impact condition is registered, the pedestrian protection system control module outputs an impact signal on the high
speed CAN bus. This signal is used by the RJB to initiate the hazard warning lamps. If this occurs, the hazard warning lamp switch is disabled for the remainder of the current ignition cycle.

If the pedestrian protection system control module detects a fault with the system, it outputs a message on the high speed
CAN bus to the instrument cluster message center. On receipt of this, the message center will display the message 'CHECK PEDESTRIAN SYSTEM'.

The pedestrian protection system control module also stores the VIN (vehicle identification number). If a new control module
is fitted to the vehicle the Jaguar approved diagnostic tool must be used to program the unit with the vehicles VIN.
When the vehicle is delivered from the factory the pedestrian protection system is in a 'safe' plant mode. Normal operating
mode should be activated using the Jaguar approved diagnostic tool during the Pre-Delivery Inspection (PDI) prior to delivery
to the customer. For additional information, refer to the PDI manual.

If any damage is caused to the front of the vehicle, be it cosmetic or structural, repairs must be carried out in line with the
processes contained in the workshop manual. Failure to carry out the correct repair process could compromise operation of the
pedestrian protection system. Refer to GTR for the latest information.

The vehicle must be left for 1 minute after disconnecting the battery before any work can be carried out on the pedestrian
protection system.

Failure Mode Detection

In service, if any fault is detected, or any part of the system is recognized as not being present, the message center displays
the warning 'Check Pedestrian System'.

The bonnet deployment actuators are non-serviceable components, and if they must be replaced due to a fault, or due to
having been deployed, or following any other accident, their barcode labels must be read and recorded in the service database
against the vehicle VIN for security purposes.

After deployment of the pedestrian protection system, the vehicle must be stopped as soon as it is safe to do so. The hazard
warning lamps will be activated and can only be switched off by pressing the engine START/STOP button to turn the engine off
and on again. A warning message 'CHECK PEDESTRIAN SYSTEM' will appear on the message center and the vehicle should be
transported to the nearest dealer/authorised repairer. The vehicle must not be driven when the bonnet has been deployed.


NOTE: If the warning message 'CHECK PEDESTRIAN SYSTEM' appears in the message center when the bonnet has not
been deployed, the vehicle should be taken to the nearest dealer/authorised repairer immediately. It can be driven.

If any significant damage occurs to the front bumper it should be inspected by a dealer/authorised repairer as soon as
possible.



CONTROL MODULE Component Description

The control module is mounted below the hood release lever behind the side trim in the left hand front footwell.

The deployment signal is received from the pedestrian protection system control module. The second-generation system
adopted for XF is all-new to Jaguar and, although similar, differs from that introduced on XK by having an accelerometer-based
sensing system rather than a contact-sensing system. The accelerometer-based system is supplied by Bosch. Mounted very
close to the skin of the bumper, it examines the characteristics of vibration waves caused by impact. Its response time is
quicker, because it does not rely on the front of the bumper being loaded. It uses the 'saved' time to make more complex
decisions, and so has fewer error states. The speed of vehicle and the length of the bonnet define the time available to get
the bonnet into its deployed and stabilized position. It is possible, therefore, to create a time-line counting back from the
predicted moment of head impact to the time when the deployment signals need to be sent. That in turn defines a time from
first contact to decision time.
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