Airbag and Seatbelt Pretensioner Supplemental Restraint System (SRS) - System Operation and

Airbag Second Stage Deployment Check

The driver and passenger front airbags each have 2 deployment stages. After an airbag deployment, it is possible that stage 1 has deployed and stage 2 has not. If a front airbag has deployed, the front airbag must be remotely deployed using the appropriate airbag disposal procedure to make sure both stages have been deployed. For information on driver airbag and/or passenger airbag remote deployment, Refer to: Pyrotechnic Device Disposal (501-20B Supplemental Restraint System, General Procedures).

SOS Post-Crash Alert System™

The SOS Post-Crash Alert System™ is controlled by the BCM, but initiated by the RCM.

When a deployment or fuel cutoff event occurs, the RCM sends a message on the HS-CAN2 (via the GWM) to the BCM. The BCM flashes the turn signal lamps and sounds the horn (except when 911 Assist™ is active) until it is turned off. The system can be turned off 10 seconds after a crash event by pressing the hazard switch. The BCM also unlocks the doors and illuminates the courtesy lamps after a crash event.

Vehicle Spin-out Detection

When internal RCM sensors detect that the vehicle has spun out, the ABS module receives this data on a dedicated HS-CAN and sends a message to the BCM on the HS-CAN2 (via the GWM). The BCM then activates the hazard warning flashers and displays a message in the IPC to indicate the hazard warning flashers are activated due to the spin-out.

Component Description

Front Impact Severity Sensor

The front impact severity sensors measure acceleration (g-rate) and are hardwired to the RCM. Mounting position and orientation is critical for correct operation of the front impact severity sensors.

Occupant Classification System (OCS)

The OCS is found only on the front passenger seat. The OCS classifies the size of the front passenger seat occupant.

The OCS is comprised of a silicone gel-filled bladder mounted between the seat cushion foam and pan, an OCSM which is mounted to the seat frame, and a pressure sensor that is internal to the OCSM. Pressure is applied to the OCS bladder when weight of any occupant or object in the front passenger seat is present. The pressure is then transferred through a tube and sensed by the OCS pressure sensor and OCSM. The components of an OCS bladder system (bladder, tube, and OCSM with integrated pressure sensor) are serviced as an assembly, and the OCS bladder system is serviced as a kit with the seat cushion and seat heater mat (if applicable).

The Belt Tension Sensor (BTS) is a Hall-effect sensor that modifies a reference voltage supplied by the OCSM. As the amount of tension applied to the belt varies, so does the voltage that returns to the OCSM. The Belt Tension Sensor (BTS) is part of the front passenger safety belt anchor and can only be serviced with the front passenger safety belt retractor and pretensioner.

Safety Belt Buckle Sensor

The safety belt buckles contain integrated sensors that are Hall-effect switches. The safety belt buckle sensors are serviced with the safety belt buckle.

Safety Belt Tension Sensor (BTS)

The safety Belt Tension Sensor (BTS) is a 3-wire Hall-effect sensor that is part of the front passenger safety belt buckle and cannot be serviced separately from the front passenger safety belt buckle assembly.

Seat Position Sensor

The seat position sensor is a Hall-effect sensor which indicates the position of the seat along the seat track. The sensor detects the presence of a shunt bracket on the track, indicating the seat has moved past a certain point in the adjustment range.

Side Impact Sensor - Front Door