On-Board Diagnostics: Notes
WARNING: This page is about a different car, the 2003 Cadillac Seville and 2003 Cadillac DeVille. 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, in most cases, illuminate the Malfunction Indicator Light (MIL) located on instrument cluster.
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 PIDs 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.