Supplemental Restraint System (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 the SRS components and circuits for correct operation.

The SRS is controlled by the RCM, which continually monitors various inputs. When these inputs indicate a 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 been activated for all occupants during a crash, it does not mean that something is wrong with the SRS.

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. The IPC illuminates the airbag warning indicator based on messaging from the RCM. The IPC also illuminates the airbag warning indicator if there is no communication between the RCM and IPC.

Secondary Airbag Warning 

A secondary airbag warning message is controlled by the IPC and displayed in the message center. If the RCM detects a SRS fault, the RCM sends a message via HS-CAN to the IPC. The IPC then illuminates the airbag warning indicator. If the IPC detects a fault with the airbag warning indicator, a DTC is stored in the IPC, then a warning message is displayed in the message center to indicate that a SRS fault is present.

Event Notification Signal 

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 FPDM, which initiates fuel cutoff and disables the fuel system.

Calling emergency services (911 assist) with APIM (SYNC-Module) 

An emergency call is triggered after an accident when the airbags are deployed or the fuel supply is interrupted. To do this, a cellular phone connected via Bluetooth must be in the vehicle. The system is obtains vehicle location information from GPS satellites and sends that information to the emergency control center in case of an accident. The emergency call is triggered by HS-CAN message received from the APIM. The APIM uses the emergency number '911' to establish a voice connection to the responsible emergency control center. As soon as the connection is established, a voice message is played, providing information about the accident and the current position.