Perform SIR Diagnostic System Check
WARNING: This page is about a different car, the 2002 GMC Savana and 2002 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
SIR diagnostic system check should always be starting point for any SIR diagnostics. It checks for proper AIR BAG warning light operation and SIR trouble codes. See SIR DIAGNOSTIC SYSTEM CHECK under DIAGNOSTIC TESTS.