Circuit Description
The battery positive voltage is supplied directly to the malfunction indicator lamp (MIL). The engine control module (ECM) turns the MIL ON by grounding the MIL control circuit.
MIL Operation
The MIL is located on the instrument panel (IP).
MIL Function
| • | The MIL informs the driver that a malfunction has occurred. The vehicle should be serviced as soon as possible. |
| • | The MIL illuminates during a bulb test, and during a system test. |
| • | A DTC will be stored if the diagnostic test requests a MIL. |
MIL Illumination
| • | The MIL will illuminate with ignition switch ON, and with the engine not running. |
| • | The MIL will turn OFF when the you start the engine. |
| • | The MIL will remain ON if the self-diagnostic system detects a malfunction. |
| • | The MIL may turn OFF if the malfunction is not present. |
| • | If the MIL is illuminated and then the engine stalls, the MIL will remain illuminated if the ignition switch is ON. |
| • | If the MIL is not illuminated and the engine stalls, the MIL will not illuminate until the ignition switch is cycled OFF, and cycled ON again. |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Controls Schematics | |||
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | |
2 | Turn ON the ignition, with the engine OFF. Does the MIL turn OFF when the ignition is turned ON? | Go to Step 5 | Go to Step 3 |
Does the MIL illuminate? | Go to Step 4 | Go to Step 7 | |
4 |
Did you find and correct the condition? | Go to Step 8 | Go to Step 6 |
5 | Repair the MIL control circuit for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 8 | -- |
6 | Replace the IPC. Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console. Did you complete the replacement? | Go to Step 8 | -- |
7 | Replace the ECM. Refer to Engine Control Module Replacement/Restore Fuel Rate Data . Did you complete the replacement? | Go to Step 8 | -- |
8 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2 |
