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. To view the SRS inputs and outputs: Refer to: Airbag and Seatbelt Pretensioner Supplemental Restraint System (SRS) - System Operation and Component Description .
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 startup. In addition to the self-test at start up, the RCM continuously monitors all of its SRS components and circuitry for correct operation.
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 High Speed Controller Area Network 2 (HS2-CAN) and High Speed Controller Area Network 3 (HS3-CAN). The IPC illuminates the airbag warning indicator based on messaging from the RCM (via the GWM. 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 displayed and controlled by the IPC. If the RCM detects a SRS fault, the RCM sends a message to the GWM, which sends it 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 and 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. On Hybrid Electric Vehicles (HEVs) or Plug-in Hybrid Electric Vehicles (PHEVs), the BECM also receives this signal.
For all vehicles, when the BCM receives the crash signal input, it initiates fuel cutoff to disable the fuel system.
For Hybrid Electric Vehicles (HEVs) and Plug-in Hybrid Electric Vehicles (PHEVs), the BECM commands the high voltage contactors open when the crash signal is received from the RCM.
After the fuel system is disabled, the vehicle can be re-started after carrying out the following steps:
- Turn the ignition OFF.
- Turn the ignition to START (on vehicles with push button start, press the start/stop button while the brake pedal is pressed).
- 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 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 High Speed Controller Area Network 2 (HS2-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®. Refer to: Seatbelt Systems - System Operation and Component Description . To deactivate or reactivate the passenger Belt-Minder® feature, Refer to: Seatbelt Minder Deactivating/Activating (413-01 Instrumentation, Message Center and Warning Chimes, General Procedures).
Passenger Airbag Deactivation (PAD) Indicator
The RCM controls the PAD indicator through a direct, hardwired 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. For information on driver airbag and/or passenger airbag remote deployment: Refer to: Pyrotechnic Device Disposal .
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 (except when 911 Assist™ is active) until it is turned off. The BCM also unlocks the doors and illuminates the courtesy lamps. Refer to: Module Controlled Functions - System Operation and Component Description .
Vehicle Spin-out Detection
When internal RCM sensors detect that the vehicle has spun out, the ABS module receives this data on a dedicated HS-CAN and sends a message to the BCM via the High Speed Controller Area Network 2 (HS2-CAN). The BCM then activates the hazard warning flashers and displays a message in the IPC to indicate the hazard warning flashers have been activated due to the spin-out.