Toyota Camry and Avalon 1997-2000

Engine Coolant Temperature (ECT) Sensor

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OPERATION

The Engine Coolant Temperature (ECT) sensor's function is to advise the ECM of changes in engine temperature by monitoring the changes in coolant temperature. The sensor must be handled carefully during removal. It can be damaged (thereby affecting engine performance) by impact.

TESTING
  1. Disconnect the engine wiring harness from the ECT sensor.
  2.  
  3. Connect an ohmmeter between the ECT sensor terminals.
  4.  
  5. With the engine cold and the ignition switch in the OFF position, measure and note the ECT sensor resistance.
  6.  
  7. Connect the engine wiring harness to the sensor.
  8.  
  9. Start the engine and allow the engine to reach normal operating temperature.
  10.  



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Fig. Separate the harness connection (2) from the ECT sensor (1)



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Fig. Attach an ohmmeter to the sensor terminals and measure the resistance



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Fig. Using an ohmmeter to check the continuity of an Engine Coolant Temperature (ECT) sensor while heating it in a water bath

  1. Once the engine has reached normal operating temperature, turn the engine OFF .
  2.  
  3. Once again, disconnect the engine wiring harness from the ECT sensor.
  4.  
  5. Measure and note the ECT sensor resistance with the engine hot.
  6.  
  7. Compare the cold and hot ECT sensor resistance measurements with the accompanying chart.
  8.  



Click image to see an enlarged view

Fig. Compare the resistance reading to this chart

  1. If readings do not approximate those in the chart, the sensor may be faulty.
  2.  

REMOVAL & INSTALLATION

NOTE
Perform this procedure only on a cold engine.

  1. Drain the coolant from the system low enough to remove the sensor.
  2.  
  3. Disconnect the sensor wiring.
  4.  
  5. Using a deep socket, remove the ECT sensor and gasket.
  6.  

To install:

  1. Install a new gasket to the sensor.
  2.  
  3. Using the deep socket, insert and secure the sensor. Tighten to 9-14 ft. lbs. (12-20 Nm).
  4.  
  5. Attach the wiring to the sensor.
  6.  
  7. Refill the cooling system.
  8.  

 
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