Circuit Description

WARNING: This page is about a different car, the 2002 Pontiac Grand Prix, 2002 Chevrolet Malibu, and 2002 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

There should be a steady Malfunction Indicator Light (MIL) with the ignition ON and the engine off. Ignition feed voltage is supplied directly to the MIL. The Powertrain Control Module (PCM) turns the MIL ON by grounding the MIL control circuit. No MIL with the key ON, engine not running suggests an open in the battery positive and ignition positive voltage feed fuses and circuits.

Perform the Engine Controls Diagnostic System Check, when the following conditions are present:

When MIL does not turn ON when ignition switch is turned to the RUN position. See above for MIL operation.
When MIL remains ON while engine is running.
When MIL is flashing while engine is running.
When a driveability symptom is determined.