Side Impact Airbag Control Module: Operation

Each side impact airbag control module (SIACM) serves as the impact sensor for its seat mounted airbag. The right side SIACM controls the right seat airbag. The left side SIACM controls the left seat airbag. Each SIACM contains two accelerometers, both accelerometers must agree in order to deploy the side airbag. In the event of a side impact, the appropriate SIACM will send a electronic signal to its airbag, deploying the airbag. The SIACM communicates with the Airbag Control Module (ACM) via the PCI bus circuit.

The SIACM perform self-diagnostics and circuit tests to determine if the system is functioning properly. If the test finds a problem, the SIACM will set both active and stored Diagnostic Trouble Codes (DTCs). If a DTC is active, the SIACM will request that the airbag warning lamp be turned on. The results of the system test are transmitted on the PCI bus circuit to the ACM once each second, or on a change in lamp state (ON/OFF). If the warning lamp status message from either SIACM contains a lamp ON request, the ACM will set an active DTC. At the same time as the DTC is set, the ACM sends a PCI bus message to the cluster requesting the airbag warning lamp to be turned ON. Observe all ACM WARNING and CAUTION statements when servicing or handling the SIACM. The SIACM's are not serviceable and must be replaced even if they are dropped.