MIL Operation

MIL is located on the Instrument Panel Cluster (IPC) and is displayed as SERVICE ENGINE SOON on Alero and Grand Am. On Impala and Monte Carlo, the MIL is displayed as an engine icon with ENGINE under the icon.

MIL Function

• The MIL informs driver that a malfunction has occurred and vehicle should be taken in for service as soon as possible.
• The MIL illuminates during a bulb test and a system test.
• A DTC will be stored if a MIL is requested by the PCM.

MIL Illumination

• The MIL will illuminate with ignition switch to RUN position and engine not running.
• The MIL will turn OFF when the engine is started.
• The MIL will remain ON if the self-diagnostic system has detected a malfunction.
• The MIL may turn OFF if the malfunction is not present.
• If MIL is illuminated and then the engine stalls, MIL will remain illuminated so long as ignition switch is in RUN position.
• If MIL is not illuminated and the engine stalls, MIL will not illuminate until ignition switch is cycled OFF, then ON.