Page 2617 of 3039

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
Page 2618 of 3039
Page 2619 of 3039
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
Page 2620 of 3039

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.
Page 2621 of 3039

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
Page 2622 of 3039

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.
Page 2623 of 3039
cushion: When the load exceeds the lower limit, but is less than the upper limit, the occupant is classified as small; when the
upper limit is exceeded, the occupant is classified as large.
Page 2624 of 3039

Published: 10-Jul-2014
Supplemental Restraint System - Air Bag and Safety Belt Pretensioner
Supplemental Restraint System (SRS)
Diagnosis and Testing
Principle of Operation
For a detailed description of the supplemental restraints system and operation, refer to the relevant Description and Operation
section in the workshop manual. REFER to: (501-20B Supplemental Restraint System)
Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS) (Description and Operation), Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS) (Description and Operation), Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS) (Description and Operation).
Inspection and Verification
WARNING: 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: Diagnosis by substitution from a donor vehicle is NOT acceptable. Substitution of control modules does not
guarantee confirmation of a fault, and may also cause additional faults in the vehicle being tested and/or the donor vehicle.
NOTE: Given the legal implications of a restraints system failure, harness repairs to Air Bag module circuits are not
acceptable. Where the text refers to "REPAIR the circuit", this will normally mean the replacement of a harness.
1. Verify the customer concern.
2. Visually inspect for obvious signs of damage and system integrity.
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to
the next step.
4. If the cause is not visually evident, check for Diagnostic Trouble Codes (DTCs) and refer to the DTC Index.
DTC Index
For a list of Diagnostic Trouble Codes (DTCs) that could be logged on this vehicle, please refer to Section 100-00.
REFER to: Diagnostic Trouble Code (DTC) Index - DTC: Restraints Control Module (RCM) (100-00 General Information, Description and Operation). Electrical
Battery condition, state of charge
Make sure all electrical connector(s) are engaged correctly on the air bag circuits
Wiring harness
Air bag module(s)
Make sure the restraints control module (RCM) is correctly installed
Fuse(s)
Sensor(s)
Pretensioner(s)
Warning lamp bulb(s) Visual Inspection
www.JagDocs.com