Using MIL
Malfunction Indicator Light (MIL) can be used for DTC retrieval and front Heated Oxygen Sensor (HO2S) monitoring. See Fig 1 . When ignition is turned on with engine off, MIL should illuminate. This is a bulb check. If MIL does not illuminate, repair MIL circuit. See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT or, see DTC P0650: MIL (CIRCUIT) under DIAGNOSTIC TESTS. When engine is started, MIL should go off. If MIL remains on, ECM has detected a malfunction. If MIL is flashing when engine is running, ECM may be in diagnostic test mode II.