Malfunction Indicator Lamp (MIL) Always On

Diagnostic Chart:

Engine Control Schematics: Power And Ground:

Engine Controls Schematics: MIL And DLC:

CIRCUIT DESCRIPTION
The malfunction indicator lamp (MIL) is illuminated if the ignition is ON and the engine is OFF. Battery ignition voltage is supplied to the MIL. The PCM will turn the MIL ON by grounding the control circuit at the PCM. The MIL should be OFF if the engine is running. A steady MIL with the engine running suggests a short to ground in the MIL control circuit, or a DTC is set in the powertrain control system.

DIAGNOSTIC AIDS
^ Check for a shorted MIL control circuit between the PCM, I/P Cluster Assembly, and the duty check data link connector.
^ A shorted IPC assembly board may cause the MIL to stay ON.
^ A faulty electrical connection to the PCM.

An intermittent malfunction may be caused by a problem in the MIL electrical circuit. Inspect the wiring harness and the components for any of the following conditions:
^ Backed out terminals
^ Incorrect mating of terminals
^ Broken electrical connector locks
^ Incorrectly formed terminals or damaged terminals
^ Faulty terminal-to-wire connections
^ Physical damage to the wiring harness
^ A broken wire inside the insulation
^ Corrosion of electrical connections, of splices, or of terminals

TEST DESCRIPTION
The numbers below refer to the step numbers in the Diagnostic Table.
1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
2. This step checks for a short to ground in MIL control circuit.
3. This step checks for a short in the MIL control circuit between the PCM and the duty check data link connector and the I/P cluster assembly.