Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. 2  - This step checks whether there is communication between PCM and a scan tool device. If PCM is unable to provide serial data to the scan tool, there will be no MIL control.
2. 3  - If other Instrument Panel Cluster (IPC) functions are not working correctly check for an open GAUGE fuse or for a lack of power and ground to IPC.
3. 4  - This step checks for an open MIL control circuit or for an internal PCM failure.
4. 5  - An open fuse determines if a voltage is constantly being applied to the control circuit.

MIL Illumination

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

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

• MIL does not illuminate when ignition switch is turned to RUN position. See MIL OPERATION .
• MIL remains illuminated while engine is running.
• MIL is flashing while engine is running.
• A driveability symptom is determined.