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 SRS 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.
When the BCM receives the crash signal input, it initiates fuel cutoff to disable 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.
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.
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 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 or side airbag needs to be deployed in the event of a crash.
The OCS is also used for operation of the passenger Belt-Minder®.
Passenger Airbag Deactivation (PAD) Indicator
The RCM controls the PAD indicator through a direct, hard-wired connection, based on information provided by the OCS. The PAD indicator illuminates to indicate the passenger airbag is disabled. An exception to this is when the front passenger seat is determined to be empty and indication of a deactivated passenger airbag is not necessary. In all other cases, the PAD indicator is off when the passenger airbag is enabled.
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.
| Occupant Size | Passenger Safety Belt Buckle Status | Passenger Airbag Status | PAD Indicator Status |
|---|---|---|---|
| Empty | Unbuckled | Disabled | Unlit |
| Empty | Buckled | Disabled | Lit |
| Small | Buckled or Unbuckled | Disabled | Lit |
| Large | Buckled or Unbuckled | Enabled | Unlit |
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.
SOS Post-Crash Alert System™
The SOS Post-Crash Alert System™ is controlled by the BCM, but initiated by the RCM.
When a deployment or fuel cutoff event occurs, the RCM sends a message on the HA-CAN to the IPC, which acts as a gateway and relays the message via the MS-CAN to the BCM. The BCM flashes the turn signal lamps and sounds the horn (except when 911 Assist™ is active) until it is turned off. The system can be turned off 10 seconds after a crash event by pressing the hazard switch. The BCM also unlocks the doors after a crash event.