Toyota Corolla 1988-1997 Repair Guide

Water Temperature Sensor

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OPERATION



The water temperature 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



See Figures 1 and 2



Click image to see an enlarged view

Fig. Fig. 1: Test the resistance of the water temperature sensor by connecting an ohmmeter between both terminals



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Fig. Fig. 2: Water temperature sensor temperature-to-resistance graph

  1. Unplug the electrical connector from the sensor.
  2.  
  3. Using an ohmmeter, measure the resistance between both terminals. Refer to the chart for the proper resistance reading.
  4.  
  5. If the resistance is not as specified, replace the sensor.
  6.  

REMOVAL & INSTALLATION



Perform this procedure only on a cold engine.

  1. Drain the cooling system as necessary.
  2.  
  3. With the ignition OFF , unplug the electrical connector to the sensor.
  4.  
  5. Using the proper sized wrench, carefully unscrew the sensor from the engine.
  6.  

To install:
  1. Coat the threads of the sensor with a sealant. Install the sensor and tighten it to 18 ft. lbs. (24 Nm).
  2.  
  3. Plug the electrical connector into the sensor.
  4.  
  5. Refill the coolant to the proper level. Road test the vehicle for proper operation.
  6.  

 
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