Side Impact Airbag Control Modules (SIACM)

The 2003 LH uses two identical side impact airbag control modules (SIACM) that share the same part number. They are located on the left and right B-post with the connector pointed forward. For proper PCI bus operation each SIACM must have a unique module identification. To provide the unique module identification the SIACM software looks for a ground on cavity # 5. If cavity # 5 is grounded the SIACM communicates as a left SIACM otherwise it communicates as a right SIACM. The SIACM perform self diagnostics and circuit tests to determine if the system is functioning properly. If the test find a problem the SIACM will set both active and stored diagnostic trouble codes. 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 to the ACM once each second or on change in lamp state. 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 mechanical instrument cluster (MIC) requesting the airbag warning lamp be turned on. Observe all ACM warning and caution statements when servicing or handling the SIACM. SIACM are not repairable and must be replaced if they are dropped.