Air Bag and Safety Belt Pretensioner SRS

AIR BAG AND SAFETY BELT PRETENSIONER SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

The air bag supplemental restraint system (SRS) is designed to provide increased 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.

Driver Air Bag Module

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

The driver air bag module:
- is steering wheel mounted.
- will deploy upon receiving a flow of current from the RCM. The restraints control module (RCM) will initiate the flow of current from signals it receives from internal RCM circuitry and internal sensors.
- has no subassemblies.

Clockspring
The clockspring:
- is mounted on the steering column, behind the steering wheel.
- allows the RCM to maintain a continuous electrical path to the driver air bag module when the steering wheel is turned.

Driver Seat Side Air Bag Module

WARNING: Do not disconnect the wire connector at the side air bag module. This is a permanent connection. Doing so may result in air bag accidental deployment, which may result in personal injury.

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 seat side air bag module:
- is installed as an assembly.
- is mounted in the driver seat back.
- will deploy upon receiving a flow of current from the RCM. The restraints control module (RCM) will initiate the flow of current from signals it receives from internal RCM circuitry and the seat side impact sensor.

Passenger Seat Side Air Bag Module

WARNING: Do not disconnect the wire connector at the side air bag module. This is a permanent connection. Doing so may result in air bag accidental deployment, which may result in personal injury.

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:
- is installed as an assembly.
- is mounted in the passenger seat back.
- will deploy upon receiving a flow of current from the RCM. The restraints control module (RCM) will initiate the flow of current from signals it receives from internal RCM circuitry and seat side impact sensor.

Passenger Air Bag Module

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:
- is installed as an assembly.
- is mounted in the passenger side of the instrument panel.
- will deploy upon receiving a flow of current from the RCM. The restraints control module (RCM) will initiate the flow of current from signals it receives from internal RCM circuitry and internal sensors.

Safety Belt Pretensioners
As part of the supplemental restraint system (SRS), the safety belt retractors are equipped with pretensioners. The pretensioners rotate the safety belt retractors to remove excess slack from the safety belt webbing. The pretensioners are activated by the restraints control module (RCM) when the module detects a frontal impact event.

Passenger Air Bag Deactivation (PAD) Switch
The passenger air bag deactivation (PAD) switch:
- is located on the instrument panel below the dual automatic temperature control (DATC) module.
- contains a light emitting diode (LED) that indicates when the PAD switch is activated (passenger air bags disabled).
- allows the passenger air bag module and the passenger seat side air bag module deployment circuits to be disabled using the ignition key.
- should be used whenever a child safety seat is being used in the front passenger seating position.

Restraints Control Module (RCM)
The restraints control module (RCM) is mounted on the center tunnel under the instrument panel. The RCM carries out the following functions:
- ignites the inflators to deploy the air bags in the event of a deployable crash event.
- activates the safety belt retractor 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 the current or historical diagnostic trouble codes (DTCs) through the data link connector (DLC).
- signals the instrument cluster 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.
- records impact data to RCM memory.

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 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 DTCs through the data link connector (DLC), using the New Generation STAR (NGS) Tester. If the air bag indicator does not function, and the system detects a fault condition, the RCM will signal the instrument cluster 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 and belt retractor pretensioners in the event that the ignition circuit is lost during impact before the RCM determines that 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 instrument cluster.

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. Two of the sensors are integral to the RCM and are not separately serviceable. In addition there are two side impact sensors one on each side of the vehicle attached to the floor pan near the seat. The RCM is mounted on the center tunnel under the instrument panel. Mounting orientation is critical for correct operation of all crash sensors.