Description of On-Board Diagnostics

The supplemental inflatable restraint (SIR) Diagnostic System Check must always be the starting point for any SIR system diagnosis. The Diagnostic System Check reveals diagnostic trouble codes through the use of a scan tool, and it also checks for proper AIRBAG warning indicator operation.

Two types of diagnostic trouble codes may be recorded:
1. Current diagnostic trouble codes represent malfunctions that are presently being detected. Current diagnostic trouble codes are stored in random access memory.
2. History diagnostic trouble codes represent all malfunctions that were detected since the last time that history memory was cleared. History diagnostic trouble codes are stored in the electronically erasable programmable read only memory (EEPROM).