With Scan Tool

The SIR Diagnostic System Check must always be the starting point of any SIR system diagnosis. The SIR Diagnostic System Check checks for proper AIR BAG warning lamp operation and checks for SIR Diagnostic Trouble Codes (DTC) using the scan tool. The following describes the difference between current and history DTCs:

^ Current DTCs - Malfunctions that are presently being detected. Random Access Memory (RAM) stores the current DTCs. Turning the ignition switch to the OFF position erases current DTCs. The presence of a current DTC will cause the Inflatable Restraint Sensing and Diagnostic Module (SDM) to turn ON the AIR BAG warning lamp.
^ History DTCs - All malfunctions detected since last clearing of history memory. Electrically Erasable Programmable Read Only Memory (EEPROM) stores the history DTCs. A scan tool clear codes command will erase history DTCs.

Some DTCs are latched and can not be cleared. Latched DTCs will require replacement of the SDM after proper diagnostics.