Passive Restraint System

AIR BAG AND SAFETY BELT PRETENSIONER SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
The air bag and safety belt pretensioner 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 advantages of the SRS.

Air Bag System Belt Pretensioner Supplemental Restraint System (SRS) Components.:

The air bag and safety belt pretensioner Supplemental Restraint System (SRS) components are shown in the Air Bag System Belt Pretensioner Supplemental Restraint System (SRS) Components image.

DRIVER AIR BAG MODULE
NOTE: References to the driver air bag module must not be confused with the side (seat-mounted) air bag components of the Supplemental Restraint System (SRS).

The driver air bag module:
^ is steering wheel mounted.
^ is a dual-stage air bag, deploying at one of two different rates depending upon crash severity, safety belt us age, and driver seat position.
^ will deploy upon receiving a signal from the Restraints Control Module (RCM).
^ has no subassemblies.

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

DRIVER SIDE AIR BAG MODULE

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).
^ When installing a new side air bag module after deployment, refer to Seats additional information.

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 as an assembly.
^ is mounted in the driver seat back.

PASSENGER AIR BAG MODULE

NOTE: References to the passenger air bag module must not be confused with the side (seat-mounted) air bag components of the Supplemental Restraint System (SRS).

The passenger air bag module:
^ is a dual-stage air bag, deploying at one of two different rates depending upon crash severity and safety belt usage.
^ will deploy upon receiving a signal from the Restraints Control Module (RCM).
^ is installed as an assembly.
^ is mounted in the passenger side of the instrument panel.

PASSENGER SIDE AIR BAG MODULE

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).
^ When installing a new side air bag after deployment, refer to Seats.

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 as an assembly.
^ is mounted in the passenger seat back.

SAFETY BELT PRETENSIONERS
As part of the Supplemental Restraint System (SRS), the safety belt buckles are equipped with pretensioners. The safety belt buckle pretensioners remove excess slack from the safety belt webbing. The pretensioners are activated by the Restraints Control Module (RCM) when the module detects a crash event force exceeding a programmed limit.

SAFETY BELT SWITCHES
As part of the Supplemental Restraint System (SRS), the safety belt buckles are equipped with switches. The safety belt switches indicate to the Restraints Control Module (RCM) whether the safety belts are connected (switch closed) or disconnected (switch open). The RCM uses this information in determining the deployment rate of the dual-stage driver and passenger air bag modules.

SEAT TRACK POSITION SENSOR
The seat track position sensor informs the Restraints Control Module (RCM) of the drivers seat position. The RCM uses this information in determining the deployment rate of the dual-stage driver air bag module.

RESTRAINTS CONTROL MODULE (RCM)
The Restraints Control Module (RCM) is mounted on the center tunnel under the instrument panel. The RCM performs the following functions:
^ signals the inflators to deploy the air bags in the event of a deployable crash.
^ activates the safety belt buckle pretensioners to remove slack from the safety belt webbing.
^ 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.
^ contains an internal safing sensor which 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 remain lit for six seconds and then go out. If an SRS fault exists, the air bag indicator will then flash the two-digit Lamp Fault Code (LFC) associated with that fault. The air bag indicator will flash the LFC five times, then remain illuminated for the rest of the key cycle. The RCM will also communicate the current and historical Diagnostic Trouble Codes (DTCs) through the Data Link Connector (DLC) using a scan tool. If the air bag indicator does not function, and the system detects a fault condition, the RCM will signal the Generic Electronic Module (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 first. After that fault has been corrected, the next highest priority fact will be displayed.

The RCM includes a backup power supply. This feature provides sufficient backup power to deploy the air bags and the safety belt pretensioners in the event that the ignition circuit is damaged in a collision before the safing and air bag sensors determine that an air bag 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 SRS components.
^ 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).

CRASH SENSORS

WARNING: THE RESTRAINTS CONTROL MODULE (RCM) ORIENTATION IS CRITICAL FOR PROPER SYSTEM OPERATION. IF A VEHICLE EQUIPPED WITH AN AIR BAG SUPPLEMENTAL RESTRAINT SYSTEM (SRS) 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 four crash sensors. One of the sensors is integral to the RCM and is not separately serviceable. A front crash sensor is located in the front-center of the vehicle, behind the grille. In addition there are two side crash sensors located underneath 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.