Supplemental Restraint System

The SRS is controlled by the RCM, which continually monitors various inputs. When these inputs indicate a frontal or side crash, the RCM may deploy some components, based upon the severity of the crash and the sensor inputs.

Although some deployable devices may not have activated for all occupants during a crash, it does not mean that something is wrong with the SRS.

The RCM performs a self-test of the complete SRS during each start-up. In addition to the self-test at start-up, the RCM continuously monitors all of its SRS components and circuitry for correct operation.

Airbag Second Stage Deployment Check 

The driver and passenger front airbags each have 2 deployment stages. After an airbag deployment, it is possible that stage 1 has deployed and stage 2 has not. If a front airbag has deployed, the front airbag must be remotely deployed using the appropriate airbag disposal procedure to make sure both stages have been deployed. For information on driver airbag and/or passenger airbag remote deployment, Refer to: Pyrotechnic Device Disposal .

Airbag Warning Indicator 

The airbag warning indicator:

• proves out by lighting for 6 seconds and then turning off.
• flashes and/or illuminates based on the message the IPC receives from the RCM.
• illuminates if the IPC does not receive a message from the RCM.

When the ignition is turned ON during normal operation, the IPC illuminates the airbag warning indicator continuously for 6 seconds. If the SRS is free of faults, the airbag warning indicator turns off and remains off. If a SRS fault exists, the airbag warning indicator illuminates and remains illuminated for the rest of the ignition cycle. The RCM communicates with the IPC via the HS-CAN and MS-CAN. The IPC illuminates the airbag warning indicator based on messaging from the RCM (through the BCM, which acts as a gateway module). The IPC also illuminates the airbag warning indicator if there is no communication between the RCM and IPC.

Event Notification Signal (Gas Vehicles) 

The event notification feature provides other vehicle subsystems with information pertaining to restraint system deployment or fuel cutoff status. When an impact occurs which exceeds a pre-determined threshold, the RCM sends a signal on a dedicated circuit to the BCM. The BCM sends a signal on a second hardwired circuit to the PCM, which initiates fuel cutoff and disables the fuel system.

After the fuel system is disabled, the vehicle can be re-started after carrying out the following steps:

• Turn the ignition ON and wait 10 seconds.
• Turn the ignition OFF.
• Turn the ignition ON.
• Turn the ignition OFF.
• Turn the ignition ON.

Event Notification Signal (Battery-Electric Vehicles) 

The event notification feature provides other vehicle subsystems with information pertaining to restraint system deployment or crash event status. When an impact occurs which exceeds a pre-determined threshold, the RCM sends a signal on a dedicated circuit to the BCM and the BECM. The BECM then commands the high voltage battery contactors open when it receives the crash signal input from the RCM.

After the contactors are opened, the vehicle powertrain can be re-started after carrying out the following steps:

• Turn the ignition ON and wait 10 seconds.
• Turn the ignition OFF.
• Turn the ignition ON.
• Turn the ignition OFF.
• Turn the ignition ON.

Occupant Classification System (OCS) 

The OCS classifies the size of the front passenger seat occupant and provides this information to the RCM.

Pressure is applied to the OCS bladder when the weight of any occupant or object in the front passenger seat is present. The pressure is then transferred through a tube and sensed by the OCS pressure sensor within the OCSM. The OCSM sends information concerning the weight of any occupant or object on the front passenger seat to the RCM via the HS-CAN. The RCM uses this information when determining if the passenger airbag needs to be deployed in the event of a crash.

The OCS is also used for operation of the passenger Belt-Minder®. For information about Belt-Minder®, Refer to: Seatbelt Systems - System Operation and Component Description . To deactivate or reactivate the passenger Belt-Minder® feature, REFER to the Owner's Literature or Refer to: Seatbelt Minder Deactivating/Activating .

Passenger Airbag Deactivation (PAD) Indicator 

The RCM controls the PAD indicator state through a direct, hardwired connection, based on information provided by the OCS. When the passenger airbag is activated, the PAD displays ON. If the RCM has deactivated the passenger airbag, the PAD indicator displays OFF.

The RCM briefly activates the PAD indicator to prove out the indicator function and verify proper functional operation of the PAD indicator to the front occupants.

The following table indicates the passenger airbag and PAD indicator status based on the size of the front passenger occupant.

Secondary Airbag Warning 

A secondary airbag warning message is displayed and controlled by the IPC. If the RCM detects a SRS fault, the RCM sends a message to the BCM, which gateways the message and sends it to the IPC memory, which then illuminates the airbag warning indicator. If the IPC detects a fault with the airbag warning indicator, a DTC is stored in the IPC and a series of chimes sound to indicate that a SRS fault is present.

SOS Post-Crash Alert System™ 

The SOS Post-Crash Alert System™ is controlled by the BCM, but initiated by the RCM.

When a deployment event occurs, the RCM sends a message on the HS-CAN to the BCM. The BCM flashes the turn signal lamps and sounds the horn until it is turned off. The BCM also unlocks the doors. Refer to: Module Controlled Functions - System Operation and Component Description .

In addition to the SOS Post-Crash Alert System™ functions, the BCM turns the interior lights on and the windshield wipers off if the vehicle is not moving after a crash has occurred.