For 1990-2009 cars

### System Description

The Powertrain On Board Diagnostic (OBD) System Check must be the starting point for any driveability complaint diagnosis. Perform a careful visual/physical check of the PCM and engine grounds for being clean and tight. Refer to Visual/Physical Check in Symptoms . Powertrain On Board Diagnostic (OBD) System Check is an organized approach to identifying a problem created by an electronic engine control system malfunction.

The Powertrain Control Module (PCM) controls the MIL by providing a ground path through the MIL control circuit to turn on the MIL. When the ignition is turned on, the MIL will remain on until the engine is running, if no Diagnostic Trouble Codes (DTC) are stored. If the MIL is illuminated, then the engine stalls, the MIL will remain illuminated so long as the ignition switch is on. DTC P0650 Malfunction Indicator Lamp (MIL) Control Circuit set suggests a malfunction in the MIL driver circuit.