On-Board Diagnostics: Notes

WARNING: This page is about a different car, the 2003 Saturn LW300 and 2003 Saturn L300. However, it is still accessible from the selected car via links, so may be relevant.

Engine Control Module (ECM) is equipped with a self-diagnostic system which detects system failures or abnormalities. When a malfunction occurs, ECM will store a Diagnostic Trouble Code (DTC) and, if code is emissions related, 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.