2010 JAGUAR XFR airbag

Driver Passenger Applicable Pretensioner Driver airbag Passenger airbag Fastened - -
Fired at pretensioner
threshold Fired at belt fastened
threshold - Unfastened - - Not fired
Fired at belt unfastened
threshold - - Fastened Occupied allow
Fired at pretensioner
threshold -
Fired at belt fastened
threshold - Fastened
Unoccupied inhibit/empty Fired at pretensioner
threshold - Not fired - Unfastened Occupied allow Not fired -
Fired at belt unfastened
threshold Unfastened
Unoccupied inhibit/empty Not fired - Not fired The battery disconnect unit is fired:

At driver and passenger airbag belt fastened threshold in a frontal impact
At the driver and passenger side impact threshold in a side impact
At the rear impact threshold in a rear impact.

Crash Signal

When the RCM outputs any of the fire signals it also outputs a crash signal to the RJB and the ECM (engine control module) on the high speed CAN. The crash signal is also hardwired to the ECM and the RJB. The instrument cluster picks up the crash signal from the high speed CAN and gateways it to the LCM (lighting control module). On receipt of the crash signal, the RJB goes into a crash mode and the ECM cuts the power supply to the fuel pump relay. In the crash mode, the RJB: Activates all of the unlock signals of the vehicle locking system, even if the vehicle is already unlocked.
Ignores all locking/superlocking inputs until it receives an unlock input, when it returns the locking system to normal
operation.
Activates the interior lamps. The interior lamps remain on permanently until they are manually switched off at the lamp
unit, or the RJB crash mode is switched off and they return to normal operation. Disables the rear window child lock input until the crash mode is switched off.
Sends a crash message to the LCM, to activate the hazard flashers. The hazard flashers remain on until cancelled by the hazard warning switch or the crash mode is switched off.
The RJB crash mode is switched off by a valid locking and unlocking cycle of the locking system.


Restraints Control Module Component Description



The RCM is installed on the top of the transmission tunnel, in line with the B pillars, and controls operation of the SRS (supplemental restraint system). The main functions of the RCM include:
Crash detection and recording
airbag and pre-tensioner firing
Self-test and system monitoring, with status indication via the airbag warning lamp and non-volatile storage of fault
information.
The RCM determines which elements of the SRS are to be deployed by using two internal areas:

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.

occupant position and the crash severity. To reduce the risk of an airbag module induced injury to a driver that is positioned
close to the steering wheel, the airbag module deploys radially. It has a non-azide propellant that reduces particulates and
effluents. It consists of a two stage inflator with separate chambers for the two inflation stages, each being independently
activated by the RCM. It has two electrical connectors that are color coded and mechanically keyed to the respective connector on the inflator.

Passenger Airbag Module



The passenger airbag module is controlled by the RCM which chooses between single or dual stage deployment, depending on the occupant status and the crash severity. It consists of a two stage inflator with two airbag electrical connectors to
accommodate the two stage inflation.

The heated gas inflator consists of a high-pressure mix of clean air and hydrogen gas, triggered by two separate ignition
squibs. It produces a controlled generation of clean gas to rapidly fill the airbag. It is classified as a stored flammable gas
(not as an explosive) and as such, has less restrictive storage and transportation requirements. It produces a very clean burn
and almost no particulates and is almost free of any toxins, making disposal or recycling much easier. Drivers Airbag Module

provides the interface connection through which the side impact sensor communicates with the RCM using serial data messages. Acceleration is evaluated by the microchip and transmitted to the restraints control module, which then makes the
decision on whether or not to activate the airbags and pretensioners.

When the ignition is switched on, the RCM supplies power to the impact sensors, which perform a self-test. After satisfactory self tests the impact sensors continually output 'digital acceleration' messages to the restraints control module. If a fault is
detected the relevant impact sensor sends a fault message, instead of the digital acceleration message, to the restraints
control module. The RCM then stores a related fault code and illuminates the airbag warning indicator. Faults can be retrieved by the Jaguar approved diagnostic system from the RCM via the high speed CAN bus connection. www.JagDocs.com

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.

Operation of the airbag warning indicator is controlled by a high speed CAN bus message from the RCM to the instrument cluster. The RCM sends the signal to illuminate the airbag warning indicator if a fault is detected, and for approximately 6 seconds during the bulb check at the beginning of each ignition cycle.

Occupant Monitoring

There are two types of occupant monitoring:

In all markets except NAS & Australia, vehicles have an occupant detection sensor
In NAS markets, vehicles have an occupant classification system

For markets which have an occupant detection sensor, this has no interface with the restraints system and only provides the
belt reminder function.

For markets that have an occupant classification system, this provides the RCM with the occupancy status of the front passenger seat. The restraints control module uses this and the seat buckle status in the evaluation of the firing strategy for
the passenger front airbag, side airbag, and pretensioner.

Safety Belt Sensors

The buckle of each front safety belt incorporates a Hall effect sensor that provides a safety belt status signal to the RCM. The RCM broadcasts the status of the two front safety belts on the high speed CAN bus for use by the instrument cluster. In the event of a front impact the RCM will deploy the pretensioners provided the safety belt buckles are fastened. The safety belt buckle pretensioners have a lower deployment threshold than that required by the airbags. Hence it is possible during a minor
collision, which exceeds the deployment threshold and will deploy only the safety belt buckle pretensioners. Airbag Warning Indicator

There is a fault with the passenger airbag firing circuit(s).
The passenger airbag is deactivated with the passenger airbag deactivation switch (where fitted).
Required by passenger seat occupant monitoring (see below).

Passenger Airbag Deactivation Switch (All Except NAS)

The passenger airbag deactivation switch provides a method of manually disabling the passenger airbag. The switch is
installed in the front passenger end of the instrument panel and operated by the ignition key.

When the passenger airbag deactivation switch is operated, it changes a ground connection between two pins in the
connectors of the RCM. When the passenger airbag deactivation switch is selected to OFF, the RCM disables the passenger airbag and, if the front passenger seat is occupied, illuminates the passenger airbag deactivation indicator.

Occupant Detection System

There are two types of occupant monitoring:

In all markets except NAS & Australia, vehicles have an occupant detection sensor
In NAS markets, vehicles have an occupant classification system

For markets which have an occupant detection sensor, this has no interface with the restraints system and only provides the
belt reminder function.

For markets that have an occupant classification system, this provides the RCM with the occupancy status of the front passenger seat. The RCM uses this and the seat buckle status in the evaluation of the firing strategy for the passenger front airbag, side airbag, and pretensioner.

The occupant classification system can determine if the front passenger seat is unoccupied, occupied by a small person, or
occupied by a large person. The occupant classification system consists of:

A pressure pad, installed under the cushion of the front passenger seat, which is connected to a pressure sensor
A safety belt tension sensor, integrated into the anchor point of the front passenger safety belt
An occupant classification module, installed under the front passenger seat.

The pressure pad is a silicone filled bladder. Any load on the pressure pad is detected by the pressure sensor.

The safety belt tension sensor is a strain gauge that measures the load applied by the safety belt anchor to the anchor bolt.
The sensor is located in the lower safety belt anchor point.

- Disadvantage: Scarring and hardening of the surface.
Flattening using a copper electrode.
- Small, sharp dents that face outwards can be worked on with a copper electrode.
Flattening using a flame and body files.

NOTE: When applied correctly, this method can be used with all the attached parts still in place (roof headlining,
wiring harnesses etc.).

- Small, soft dents (only slight stretching): Working at the edges of the dent in an inward spiral pattern, the dent
is heated with an oxyacetylene torch (torch size 1 - 2 mm, excess gas flame) to approx. 250° C.
- Working rapidly with a body file extracts heat from the edge area until the dent is flattened. Preferably alternate
between two files. This increases the amount of heat that can be extracted.

Safety measures

The electronic control modules (ECM) fitted to vehicles make it advisable to follow suitable precautions prior to carrying
out welding repair operations. Harsh conditions of heat and vibration may be generated during these operations which
could cause damage to the modules. In particular, it is essential to follow the appropriate precautions when
disconnecting or removing the airbag RCM.
Do not allow electronic modules or lines to come into contact with the ground connection or the welding electrode.
Seat belt anchorages are a safety critical. When making repairs in these areas, it is essential to follow design
specifications. Note that extra strength low alloy steel may be used for seat belt anchorages. Where possible, the
original production assembly should be used, complete with its seat belt anchorages, or the cut line should be so
arranged that the original seat belt anchorage is not disturbed.
All welds within 250mm (9.842) of seat belt anchorages must be carefully checked for weld quality, including spacing of
spot welds.
Remove the battery before carrying out welding work in its vicinity.
Utmost care must be taken when welding near the fuel tank or other components that contain fuel. If the tank filler
neck or a fuel line must be detached to allow access for welding work, then the fuel tank must be drained and removed.
Never weld, on components of a filled air conditioning system. The same applies if there is a risk of the air conditioning
system heating up.
Connect the ground connection of the electrical welder directly to the part that is to be welded. Make sure that there
are no electrically insulating parts between the ground connection and the welding point.
Adjacent vehicle parts and adjacent vehicles must be shielded against flying sparks and heat.

Pedestrian protection system

The pedestrian protection system is designed to mitigate injuries in a pedestrian collision with the vehicle. It does this by
utilizing a pair of pyrotechnic actuators to lift the hood away from the engine, creating a cushioned impact between the
pedestrian and the vehicle. It is essential that any repair or replacement operations do not affect the safe working of the
system.
For additional information, refer to: Pedestrian Protection System (501-20C Pedestrian Protection System, Description and Operation).

Resistance spot welding

Where resistance spot welds have been used in production, they must be reproduced with new spot welds in replacement
where possible. All such reproduction spot welds should be spaced 25 to 30mm apart.
Setting up the equipment and co-ordinating the welding parameters.

Equipment:
- Follow the equipment manufacturer's instructions for the equipment settings.
- Select the correct electrode arms (as short as possible).
- Align the electrode arms and tips exactly.
- Electrode tips should be convex (rough shaping with a file, fine shaping with a sanding block).
Body:
- Make sure that the flanges to be joined lie perfectly flat to one another.
- Prepare a bare metal joint surface (inside and outside).
Notes on technique/method:
- Carry out a test weld on a sample piece of the material coated in welding paste.
- If any metal parts are located between the electrode arms then there will be a loss of induction and therefore
power (adjust current setting).
- The power needs to be adjusted for high-strength low alloy steel.
- Repeated welding on old welding points often leads to poor quality welds.
- Keep the electrode tips as near as possible to an angle of 90° to the contact surface.
- Keep the pressure on the electrodes for a short period after finishing the weld.
- The electrodes work best if their shape is convex. Clean the contact surface of the electrodes regularly.
Resistance spot welding panels where the total thickness is 3 mm or more

For all repairs to modern Jaguar vehicles, spot-welding equipment should be suitable for reliable welding of zinc-plated,
high-strength and high-tensile steels in three or more layers, up to 5 mm total thickness. If these requirements are not
fulfilled, plug welding must be used for safety reasons. The electrical specifications (current, resistance, heat) of the
spot-welding equipment have different validity, depending upon the type of equipment. Therefore, it is essential that the
manufacturer's instructions are observed with regard to the actual welding performance.
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