SRS Components

Air Bag Module - Driver
The driver air bag module:
Is replaced as an assembly.
Is mounted in the center of the steering wheel.

Steering Wheel Trim Cover
The steering wheel trim cover:
Encases the driver air bag module and horn switch.
Has tear seams that separate to allow inflation of the air bag.
Must not be repainted for any reason.
Is a component of the driver air bag module and is not repaired separately.

Air Bag
The air bag:
Is constructed of nylon.
Is a component of the driver air bag module and is not replaced separately.

Inflator
The inflator:
Receives electrical energy when the air bag sensor is activated.
Contains an igniter that converts the electrical signal to thermal energy (heat), causing the ignition of the inflator gas generant.
Inflates the air bag after the sodium azide/copper oxide combustion occurs.
Is a component of the driver air bag module and is not replaced separately.

Mounting Plate and Retainer Ring
The mounting plate and retainer ring:
Attach and seal the air bag to the inflator.
Attach the trim cover.
Mount the entire driver air bag module to the steering wheel.
Are components of the driver air bag module and are not replaced separately.

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 driver air bag module to the air bag sensor.

Air Bag Module - Passenger
The passenger air bag module:
Is replaced as an assembly.
Is mounted in the RH side of the instrument panel (04320).

Deployment Door
The deployment door:
Is an integral part of the instrument panel with a textured finish.
Has a tear seam that separates when the air bag inflates, and hinges out of the way during deployment.
Retains the air bag in the reaction housing until deployment.
Must not be repainted for any reason.
Is a component of the passenger air bag module and is not replaced separately.

Air Bag
The air bag:
Is constructed of nylon.
Is a component of the passenger air bag module and is not replaced separately.

Inflator
The inflator:
Receives electrical energy when the air bag sensor is activated.
Contains an igniter that converts the electrical signal to thermal energy (heat), causing the ignition of the inflator gas generant.
Inflates the air bag after the chemical reaction takes place.
Is a component of the passenger air bag module and is not replaced separately.

Reaction Housing
The reaction housing:
Provides support for the inflator.
Provides a reaction surface for the passenger air bag module.
Is used to attach the deployment door.
Contains mounting brackets that attach the passenger air bag module to the instrument panel.
Is a component of the passenger air bag module and is not replaced separately.

Air Bag Electronic Crash Sensor (ECS)
The air bag electronic crash sensor (ECS) module carry outs 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 in the lighting control module (LCM) if the air bag indicator is not available and another SRS fault exists.


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. When the ignition is cycled (turned off and then turned on) after the 8 second prove out (6 seconds on, 2 seconds off), 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 Portable Diagnostic Unit (PDU). 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 and 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 function in the ECS (RCM) closes. The Back Up Power Supply (BPS) gives sufficient power for 150 milli-seconds to close safing functions to fire or deploy air bags. 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 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 On Board Diagnostics Two (OBD II) connector.
Provides the electrical path from the ECS to the vehicle emergency system (VEMS).

Sensor


(!) WARNING:
THE ECS MODULE DOES NOT NEED TO BE REPLACED IF THE AIR BAG MODULES HAVE DEPLOYED. THE ONLY TIME THE ECS MODULE MUST BE REPLACED IS WHEN THE SYSTEM HAS INCURRED FIVE SEPARATE DEPLOYMENTS.


(!) 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 AND CORRECT LOCATION. IF DAMAGED, THE ECS MUST BE REPLACED WHETHER OR NOT THE AIR BAG MODULES HAVE DEPLOYED. IN ADDITION, MAKE SURE THE AREA OF THE ECS 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.