TESTING

1. Disconnect the engine wiring harness from the ECT sensor.
2. Connect an ohmmeter between the ECT sensor terminals.
3. With the engine cold and the ignition switch in the OFF position, measure and note the ECT sensor resistance.
4. Connect the engine wiring harness to the sensor.
5. Start the engine and allow the engine to reach normal operating temperature.
6. Once the engine has reached normal operating temperature, turn the engine OFF.
7. Once again, disconnect the engine wiring harness from the ECT sensor.
8. Measure and note the ECT sensor resistance with the engine hot.
9. Compare the cold and hot ECT sensor resistance measurements with the accompanying chart.

   Fig. 1: Engine Coolant Temperature (ECT) sensor values

10. If readings do not approximate those in the chart, the sensor may be faulty.

    Fig. 2: Test both terminals of the coolant temperature sensor using an ohmmeter