Circuit/System Testing

Monitor the scan tool for any other DTCs.
- If DTC P0660 is set, diagnose that DTC first. Refer to DTC P0660 .
Ignition ON, disconnect the IMT valve harness connector and measure for 0.5 volt on the variable tuning signal circuit and ground.
- If less than 0.5 volt, test the variable tuning signal circuit for a short to ground, or a faulty control module.
Measure for 5.0 volts on the IMT fan position signal circuit at the IMT valve harness connector.
- If more than 5 volts, test the IMT fan position signal circuit for a short to voltage.
Disconnect the engine control module (ECM) harness connector for the IMT fan position signal circuit and measure the resistance of the circuit.
- If more than 5 ohms, repair the high resistance condition.