On-Board Diagnostics: Notes
WARNING: This page is about a different car, the 2002 Pontiac Grand Am, 2002 Oldsmobile Alero, 2002 Chevrolet Monte Carlo, and 2002 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
PCM is equipped with a self-diagnostic system which detects system failures or abnormalities. When a malfunction occurs, PCM will store a Diagnostic Trouble Code (DTC) and, if code is emissions related, the Malfunction Indicator Light (MIL) located on instrument cluster will illuminate.
There are 2 paths for accessing on-board diagnostics. It is necessary to access information through both paths, as each path presents some different information.
- Generic OBD-II
This provides all generic codes and some OEM codes, serial data required for generic OBD-II and some OEM PIDs, monitor status, pending codes and freeze frame. - OEM
All DTCs, all PIDs, failure records, enhanced scan tool information and all other OEM scanner functions.