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 advantages of the SRS.

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

Air Bag Supplemental Restraint System (SRS) Components

Air Bag Supplemental Restraint System (SRS) Components

• is installed as an assembly.
• is mounted in the center of the steering wheel (3600).

Clockspring

The clockspring (14A664):

• is mounted on the steering column, behind the steering wheel.
• continuously transfers electrical signals from the driver air bag module to the air bag sensor.

Passenger Air Bag Module

The passenger air bag module:

• is installed as an assembly.
• is mounted in the RH side of the instrument panel (04320).

Air Bag Electronic Crash Sensor (ECS)

The air bag electronic crash sensor (ECS) module performs the following functions:

• discriminates between an event that warrants frontal air bag deployment and an event that does not.
• 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 and historical DTCs.
• activates a chime if the air bag indicator is not available.

NOTE: The safing sensor is internal to the ECS and is not serviced separately.

The ECS monitors the SRS for possible faults. If a fault is detected while the ignition switch is in the RUN position, the ECS will illuminate the air bag indicator located in the instrument cluster (10849). When the ignition is cycled (turned off and then turned on), the air bag indicator will flash the two-digit lamp fault code (LFC). The air bag indicator will flash the LFC five times, then it will remain illuminated for the rest of the key cycle. The ECS 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 ECS will activate an audible chime. The chime is a series of five sets of five tone bursts. If the chime or buzzer is heard, the SRS or the air bag indicator requires service.

Lamp fault codes 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 ECS includes an internal backup power supply. This feature provides sufficient backup power to deploy the air bags in the event the battery or battery cables are damaged in a collision before the safing and air bag sensors close. 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 (10655) and the ignition.
provides the electrical path from the ECS to the air bag modules.
provides the electrical path from the ECS to the air bag indicator and data link connector (DLC).
provides the electrical path from the ECS to the total warning system (TWS).

Sensor

WARNING: A new ECS module must be installed if the air bag modules have deployed.

WARNING: The ECS orientation is critical for correct system 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, a new ECS must be installed whether or not the air bag modules have deployed. In addition, make sure the area of the sensor mounting is restored to its original condition.

The SRS contains two sensors which are contained in the ECS. The ECS is mounted on the center tunnel under the instrument panel.