Circuit/System Testing
- Ignition OFF, disconnect the harness connector of the engine control module (ECM).
- Ignition OFF, connect the J 33431-C
to the engine coolant temperature gage output signal circuit at the ECM harness connector and a good ground.
- Ignition ON, set the J 33431-C
to generate a speedometer signal. The engine coolant temperature gage should change.
- If the gage changes, replace the ECM
- If the gage does not change, test the engine coolant temperature gage output signal circuit for the following conditions:
- Open
- Short to ground
- Short to voltage
- High resistance
- If the circuit/connections test normal, replace the IPC.