SIR Diagnostic Flow

Caution: In order to avoid deploying the air bag when troubleshooting the SIR system, use only the equipment specified and the instructions given Failure to use the specified equipment as instructed could cause air bag deployment, personal injury to you or someone else, or unnecessary SIR system repairs.
Begin all SIR system diagnosis with the SIR Diagnostic System Check. Performing the SIR Diagnostic System Check determines the operational status of the SIR system by checking the following functions:
^ Operation of the AIR BAG warning lamp
^ Communication with the scan tool through the serial data line
^ The presence of diagnostic trouble codes (current or history)

Current diagnostic trouble codes indicate malfunctions occurring right now. The presence of a current DTC causes illumination of the AIR BAG warning lamp. Current diagnostic trouble codes are stored in Random Access Memory (RAM). Turning the ignition switch off erases current diagnostic trouble codes.

History diagnostic trouble codes indicate malfunctions which have occurred since the last time DTCs were cleared but are not presently being detected. The presence of a history DTC does not cause illumination of the AIR BAG warning lamp. History diagnostic trouble codes are stored in the Electrically Erasable Programmable Read-Only Memory (EEPROM). Scan tool clear codes command will erase history diagnostic trouble codes.