Malfunction Indicator Lamp (MIL) Inoperative

CIRCUIT DESCRIPTION
There should always be a steady malfunction indicator lamp (MIL) when the ignition switch is in the ON position and the engine is not running. System voltage is applied to the indicator bulb and the powertrain control module (PCM) provides a path to ground. Once the engine starts, the PCM turns the OFF the MIL. When an engine control system malfunction occurs, the PCM turns ON the MIL and a diagnostic trouble code is stored in memory.

DIAGNOSTIC AIDS
An intermittent malfunction may be caused by a faulty electrical connection in the MIL circuit. Refer to Intermittent Conditions. Intermittent Conditions

TEST DESCRIPTION

Steps 1-3:

Steps 4-10:

Step 11:

The numbers below refer to the step numbers on the diagnostic table.
2. This step checks whether there is communication between the PCM and a scan tool device. If the PCM is unable to provide serial data to the scan tool, there will be no MIL control.
3. If other instrument panel cluster (IPC) functions are not working correctly check for an open GAGE fuse or for a lack of power and ground to the IPC.
4. This step checks for an open MIL control circuit or for an internal PCM failure.
5. An open fuse determines if a voltage is constantly being applied to the control circuit.