Toyota Corolla 1988-1997 Repair Guide

Intake Air Temperature (IAT) Sensor

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OPERATION



The IAT sensor advises the ECM of changes in intake air temperature (and therefore air density). As air temperature of the intake varies, the ECM, by monitoring the voltage change, adjusts the amount of fuel injection according to the air temperature.

TESTING



See Figures 1 and 2

  1. Unplug the electrical connector from the IAT sensor, then remove the sensor from the air cleaner.
  2.  



Click image to see an enlarged view

Fig. Fig. 1: Submerge the sensor tip in water and check for the proper resistance between the terminals

  1. Using an ohmmeter, measure the resistance between both terminals. Refer to the chart for the proper resistance reading.
  2.  



Click image to see an enlarged view

Fig. Fig. 2: Intake Air Temperature (IAT) sensor temperature-to-resistance graph

  1. If the resistance is not as specified, replace the sensor.
  2.  

REMOVAL & INSTALLATION



  1. Remove the air cleaner cover.
  2.  
  3. With the ignition OFF , unplug the electrical connector.
  4.  
  5. Push the IAT sensor out from inside the air cleaner housing.
  6.  

To install:
  1. Install the sensor, making sure it is properly placed and secure.
  2.  
  3. Connect the wiring harness, and install the air cleaner cover.
  4.  

 
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