Air Bag Supplemental Restraint System (SRS)

Air Bag Supplemental Restraint System (SRS) Components:

The air bag Supplemental Restraint System (SRS) is designed to provide increased collision protection for front seat occupants in addition to that provided by the three-point safety belt system. Safety belt use is necessary to obtain the best occupant protection and to receive the full advantage of the SRS.

The air bag supplemental restraint system (SRS) components are shown in the illustration.







Air Bag Module - Driver

NOTE: References to the driver air bag module must not be confused with the seat-mounted air bag components of the supplemental restraint system (SRS).

The driver air bag module:
^ is installed new as an assembly.
^ is mounted in the center of the steering wheel.

Clockspring
The clockspring:
^ is mounted on the steering column, behind the steering wheel.
^ provides a continuous electrical path between the restraints control module (RCM) and the driver air bag module.

Air Bag Module - Driver Side

NOTE: References to side air bag modules refer to the seat-mounted and not to the steering wheel or instrument panel mounted air bag components of the supplemental restraint system (SRS).

The driver side air bag module:
^ has no separately repairable parts and is installed as an assembly.
^ is mounted in the driver seat back.

Air Bag Module - Passenger Side

NOTE: References to side air bag modules refer to the seat-mounted and not to the steering wheel or instrument panel mounted air bag components of the supplemental restraint system (SRS).

The passenger side air bag module:
^ has no separately repairable parts and is installed as an assembly.
^ is mounted in the passenger seat back.

Passenger Air Bag Module:

Air Bag Module - Passenger

NOTE: References to the passenger air bag module must not be confused with the seat-mounted air bag components of the supplemental restraint system (SRS).

The passenger air bag module:
^ has no separately repairable parts and is installed as an assembly.
^ is mounted in the RH side of the instrument panel.

Restraints Control Module (RCM)
The restraints control module (RCM) carries out the following functions:
^ signals the inflators to deploy the air bags in the event of a deployable crash.
^ monitors the air bag supplemental restraint system (SRS) for faults.
^ illuminates the air bag indicator if a fault is detected.
^ flashes the air bag indicator to indicate the Lamp Fault Code (LFC) detected.
^ communicates through the Data Link Connector (DLC) the current or historical Diagnostic Trouble Codes (DTCs).
^ signals the Generic Electronic Module (GEM) to activate a chime if the air bag indicator is not available and another SRS fault exists.

NOTE: The safety sensor is internal to the RCM and is not serviced separately.

The RCM monitors the SRS for possible faults. If a fault is detected while the ignition switch is in the RUN position, the RCM will flash the air bag indicator located in the instrument cluster.

When the ignition is cycled (turned off and then on), the air bag indicator will prove out by lighting for six seconds and then off for two seconds. After the prove out, the air bag indicator will then flash the two-digit LFC for any current SRS fault. If an SRS fault exists, the air bag indicator will flash the LFC five times, and then remain illuminated for the rest of the key cycle. The RCM will also communicate the current and historical DTCs through the DLC, to the scan tool. If the air bag indicator does not function, and the system detects a fault condition, the RCM will signal the GEM to activate an audible chime. The chime is a series of five sets of five tone bursts. If the chime is heard, the SRS and the air bag indicator require repair.

LFCs are prioritized. If two or more faults occur at the same time, the fault having the highest priority will be displayed. After that fault has been corrected, the next highest priority fault will be displayed.

The RCM includes a backup power supply. This feature provides sufficient backup power to deploy the air bags in the event that the ignition circuit is damaged in a collision before the safing and air bag sensors determine that a deployment is required. The backup power supply will deplete its stored energy approximately one minute after the battery ground cable is disconnected.

Electrical System
The electrical system that supports the air bag supplemental restraint system (SRS):
^ is powered from the battery through the ignition circuit.
^ provides the electrical path from the restraints control module (RCM) to the air bag modules.
^ provides the electrical path from the restraints control module (RCM) to the side crash sensors (if equipped).
^ provides the electrical path from the RCM to the air bag indicator.
^ provides the electrical path from the RCM to the data link connector (DLC).
^ provides the electrical path from the RCM to the generic electronic module (GEM).

Impact Sensors

WARNING: MOUNTING ORIENTATION OF THE IMPACT SENSORS AND THE RCM IS CRITICAL FOR PROPER SYSTEM OPERATION. IF A VEHICLE HAS BEEN INVOLVED IN A COLLISION IN WHICH THE CENTER TUNNEL AREA HAS BEEN DAMAGED, INSPECT THE RCM MOUNTING AREA FOR DEFORMATION. INSPECT THE IMPACT SENSOR MOUNTING AREA FOR DAMAGE. IF DAMAGED, THE RCM AND SENSORS MUST BE REPLACED WHETHER OR NOT THE AIR BAGS HAVE DEPLOYED. IN ADDITION, MAKE SURE THE MOUNTING AREA OF THE RCM AND IMPACT SENSORS ARE RESTORED TO THE ORIGINAL PRODUCTION CONFIGURATION.

The impact sensors provide data to the RCM for use in calculating impact severity. This is accomplished using various electrical and electro-mechanical sensors located throughout the vehicle. Side impact sensors are located on the LH and RH B-pillars.