Malfunction Indicator Lamp Always On: Description
WARNING: This page is about a different car, the 2002 Pontiac Montana, 2002 Oldsmobile Silhouette, and 2002 Chevrolet Venture. However, it is still accessible from the selected car via links, so may be relevant.
The Powertrain Control Module (PCM) controls the Malfunction Indicator Lamp (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 as long as the ignition is ON.