On-Board Diagnostics: Notes

The Alternative Fuels Engine Control Module (AF ECM) is equipped with a self-diagnostic system which detects system failures or abnormalities. When a malfunction occurs, the AF ECM will store a Diagnostic Trouble Code (DTC) and, if code is emissions related, illuminate the Malfunction Indicator Lamp (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.