GM Corsica/Beretta 1988-1996 Repair Guide

Intake Air Temperature (IAT) Sensor

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OPERATION



See Figure 1

The IAT sensor is a thermistor which supplies intake air temperature information to the PCM. The sensor produces high resistance at low temperatures and low resistance at high temperatures. The PCM supplies a 5 volt signal to the sensor and measures the output voltage. The voltage signal will be low when the air is cold and high when the air is hot. The IAT is located in or near the air intake duct.



Click image to see an enlarged view

Fig. Fig. 1: Intake Air Temperature (IAT) sensor (3), connector (1) and locking tab (2)

TESTING



See Figure 2

  1. Remove the Intake Air Temperature (IAT) sensor from the vehicle.
  2.  
  3. Connect a digital ohmmeter to the two terminals of the sensor.
  4.  
  5. Using a calibrated thermometer, compare the resistance of the sensor to the temperature of the ambient air. Refer to the temperature vs. resistance chart.
  6.  
  7. Repeat the test at two other temperature points, heating or cooling the air as necessary with a hair dryer or other suitable tool.
  8.  
  9. If the sensor does not meet specifications, it must be replaced.
  10.  

REMOVAL & INSTALLATION



  1. Disconnect the negative battery cable.
  2.  
  3. Detach the sensor electrical connector locking tab and/or unplug detach the connector.
  4.  
  5. If equipped, unfasten the retaining clamp.
  6.  
  7. Carefully remove the sensor.
  8.  

To install:
  1. Install the sensor.
  2.  
  3. Attach the electrical connector.
  4.  
  5. Connect the negative battery cable.
  6.  

 
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