Malfunction Indicator Lamp (MIL) Always On
Diagnostic Instructions
Circuit/System Description
Ignition 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. There should be a steady MIL with the ignition ON and the engine OFF.
MIL Operation
The MIL is located in the Instrument Panel Cluster.
MIL Function
• | The MIL informs the driver that a malfunction has occurred and the 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 diagnostic. |
MIL Illumination
• | The MIL will illuminate with the ignition switch ON and the 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 no longer present. |
• | If the MIL is illuminated and then the engine stalls, the MIL will remain illuminated as long as 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, then ON. |
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, command the P16 Instrument Cluster MIL ON and OFF with a scan tool. The MIL should turn ON and OFF as commanded.
Circuit/System Testing
- Ignition OFF, disconnect the X2 harness connector at the K20 Engine Control Module.
- Ignition ON, observe the malfunction indicator lamp (MIL).
⇒ | If the MIL stays illuminated, test the MIL control circuit terminal 48 for a short to ground between the ECM and the P16 Instrument Cluster. If the circuit tests normal, replace the P16 Instrument Cluster. |
⇒ | If the MIL is no longer illuminated, replace the K20 Engine Control Module. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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