The Engine Coolant Temperature (ECT) sensor resistance changes in response to engine coolant temperature. The sensor resistance decreases as coolant temperature increases. This provides a reference signal to the ECM, which indicates engine coolant temperature.
See Figure 1 and 2
- Disconnect the engine electrical harness from the ECT sensor.
- Connect an ohmmeter between the ECT sensor terminals.
- With the engine cold and the ignition switch in the OFF position, measure and note the ECT sensor resistance.
- Connect the engine electrical harness to the sensor.
- Start the engine and allow it to reach normal operating temperature.
- Once the engine has reached normal operating temperature, turn it OFF .
- Once again, disconnect the engine electrical harness from the ECT sensor.
- Measure and note the ECT sensor resistance with the engine hot.
- Compare the cold and hot ECT sensor resistance measurements with the accompanying chart.
- If readings do not approximate those in the chart, the sensor may be faulty.
REMOVAL & INSTALLATION
See Figures 3
- Partially drain the engine cooling system until the coolant level is below the ECT sensor mounting hole.
- Disconnect the negative battery cable.
- Disconnect the electrical harness from the ECT sensor.
- Remove the coolant temperature sensor from the cylinder head.
- Coat the sensor threads with Teflon sealant.
- Thread the sensor into the intake manifold and tighten securely.
- Connect the negative battery cable.
- Refill the engine cooling system.
- Start the engine and check for coolant leaks.
- Top off the cooling system.