Air Bag Supplemental Restraint System (SRS) Components

Air Bag Supplemental Restraint System (SRS)

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 following 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 steering wheel mounted.
^ will deploy upon receiving a signal from the restraints control module (RCM).
^ has no subassemblies.
^ is serviced with the steering wheel as an assembly.

Clockspring

The Clockspring:
^ is mounted on the steering column, behind the steering wheel.
^ continuously transfers electrical signals from the driver air bag module to the Restraints Control Module (RCM).

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:
^ will deploy upon receiving a signal from the restraints control module (RCM) initiated by the driver side crash sensor.
^ is installed new as an assembly.
^ is mounted in the driver seat back.

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.

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:
^ will deploy upon receiving a signal from the restraints control module (RCM) initiated by the passenger side crash sensor.
^ is installed new as an assembly.
^ is mounted in the passenger seat back.

Restraints Control Module (RCM)

The Restraints Control Module (RCM) performs 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 Lighting Control Module (LCM) to activate a chime if the air bag indicator is not available and another SRS fault exists.

NOTE: The safing 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 illuminate the air bag indicator located in the instrument cluster.

When the ignition is cycled (turned off and then on), the air bag indicator will proveout. The air bag indicator will light for six seconds, go off for two seconds. If a system fault exists the air bag indicator will then flash the two-digit LFC. The air bag indicator will flash the LFC five times, then it will 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 Lighting Control Module (LCM) 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 first. 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 1 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 Lighting Control Module (LCM).

Sensor

WARNING: THE RESTRAINTS CONTROL MODULE (RCM) ORIENTATION IS CRITICAL FOR PROPER AIR BAG SUPPLEMENTAL RESTRAINT SYSTEM (SRS) OPERATION. IF A VEHICLE EQUIPPED WITH AN SRS SYSTEM HAS BEEN INVOLVED IN A COLLISION IN WHICH THE CENTER TUNNEL AREA HAS BEEN DAMAGED, INSPECT THE MOUNTING AND BRACKET FOR DEFORMATION. IF DAMAGED, THE RCM MUST BE REPLACED WHETHER OR NOT THE AIR BAGS HAVE DEPLOYED. IN ADDITION, MAKE SURE THE AREA OF THE RCM MOUNTING IS RESTORED TO ITS ORIGINAL CONDITION.

For this vehicle, the SRS employs three crash sensors. One of the sensors is integral to the RCM and is not serviceable separately. In addition, there are two side crash sensors located under the front driver and passenger seats. The RCM is mounted on the center tunnel under the instrument panel. Mounting orientation is critical for correct operation of all crash sensors.