Notice: Never us an SDM that is damaged or has been subjected to water intrusion. The use of an SDM that is damaged or has been subjected to water intrusion can result in a malfunctioning SIR system and cause vehicle damage.

When the sensing and diagnostic module (SDM) detects any problem it illuminates the AIRBAG warning indicator and stores the diagnostic trouble codes (DTCs). The supplemental inflatable restraint Diagnostic System Check--SIR must always be the starting point for any SIR diagnosis. The Diagnostic System Check-SIR reveals diagnostic trouble codes (DTCs) through the use of a scan tool. It also checks for proper AIRBAG warning lamp operation.

The two types of DTCs that may be recorded are as follows:

Historic DTCs are stored in the electrically erasable programmable read-only memory (EPPROM).

A scan tool can read serial data from terminal 9 of the data link connector (DLC). The scan tool is used to read diagnostic trouble codes (DTCs), and to clear some DTCs after a repair is completed. By design, DTC 51 and 53 cannot be cleared. And the DTC 61 cannot be cleared for the ignition cycle once the DTC has bee detected by the SDM.

To use the scan tool, turn OFF the ignition, connect the scan tool to the DLC, and turn the ignition switch to ON.

Follow the instructions in the scan tool manual. The SDM sends serial data from terminal A4 of the SDM to terminal 9 of the DLC.

Notice: Do not use a scan tool that displays faulty data. Report the scan tool problem to the manufacturer. Use of a faulty scan tool can result in misdiagnosis and unnecessary parts replacement.

Use a scan tool to read and clear diagnostic trouble codes (DTCs). A connector adapter kit provides jumper wires and terminal adapters to make it easier to test small terminals.

In diagnostic testing, use a load tool or dummy resistance to substitute for airbag modules.