With Driver & Passenger SIR System

All current diagnostic trouble codes except current DTC 51 (accident detected) clears automatically when the fault causing the DTC is correctly diagnosed,

corrected and all conditions to clear have been satisfied. Current DTC 51 requires a scan tool to clear.

How To Clear History Diagnostic Trouble Codes

History diagnostic trouble codes can only be cleared by using a scan tool. If a scan tool is not available, inform the owner and suggest that the diagnostic trouble codes be cleared upon the next visit to a GM dealership. All history diagnostic trouble codes except history DTC 52 (accident detected) can be cleared by using a scan tool. History DTC 52 cannot be cleared.

Flash Diagnostic Trouble code Diagnostics

Flash DTC diagnostics can only be used to read current diagnostic trouble codes and to determine when history diagnostic trouble codes are present. Flash DTC diagnostics cannot be used to clear diagnostic trouble codes or read history diagnostic trouble codes. Flash DTC diagnostics is enabled by grounding data link connector (DLC) terminal K with the ignition switch "ON." Grounding DLC connector terminal K pulls the DERM's "Diagnostic Request" input (terminal A8) low and signals the DERM to enter the flash DTC diagnostic display mode.

The DERM displays the diagnostic trouble codes by flashing the "INFLATABLE RESTRAINT" warning lamp with a lamp driver at the "SIR Indicator" output (terminal B1). Each DTC that is displayed consists of flashes which represents the tens, or first DTC digit; then a 1/2 second pause, followed by flashes which represents the ones or second DTC digit. Each DTC is flashed once before moving on to the next DTC. After all diagnostic trouble codes have been displayed, the entire DTC sequence is continually repeated until ground is removed from DLC connector terminal K.

Two special diagnostic trouble codes exist when reading in the flash DTC mode (flash DTC 12 and flash DTC 13). DTC 12 is always the first DTC displayed when the flash DTC mode is enabled. DTC 12 is not an SIR fault indication, but an indication that the flash DTC mode has been enabled. When there are no current or history diagnostic trouble codes present, the DERM displays DTC 12 until ground is removed from DLC connector terminal K. Flash DTC 13 displays only if there are history diagnostic trouble codes that are not current. To read the history diagnostic trouble codes a scan tool must be used.