Restraints Control Module (RCM)
The RCM carries out the following functions:
- deploys the air bag(s)/safety canopies in the event of a deployable collision.
- activates the safety belt buckle pretensioner and safety belt adaptive load limiting retractor to control tension on the safety belt in the event of a deployable collision.
- monitors the SRS for faults.
- sends a message to the instrument cluster module to flash/illuminate the air bag warning indicator if a fault is detected.
- communicates through the data link connector (DLC) the current or historical DTCs.
The RCM monitors the SRS for possible faults. If an SRS fault exists, the RCM sends a message to instrument cluster module to flash a coded sequence which is called a LFC on the air bag warning indicator.
When the ignition is cycled (turned OFF and then ON), the instrument cluster will prove out the air bag warning indicator by lighting for 6 seconds and then turn off. If a current SRS fault exists, the RCM requests illumination of the air bag warning indicator and will remain illuminated for the rest of the key cycle. The RCM will also communicate the on-demand (current) and continuous (historical) DTCs through the DLC, to the scan tool. If the RCM requests illumination of the air bag warning indicator and the air bag warning indicator does not function, the instrument cluster module will automatically activate an audible chime. The chime is a series of 5 sets of 5 tone bursts. If the chime is heard, the SRS and the air bag warning indicator require repair.
The RCM includes a backup power supply. This feature provides sufficient backup power to deploy the air bags in the event that the ignition circuit is lost or damaged during impact. The backup power supply will deplete its stored energy approximately one minute after power and/or ground has been removed from the RCM.