GM Corvette 1984-1996 Repair Guide

Intake Air Temperature (IAT) Sensor

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OPERATION



On earlier model vehicles, the sensor is referred to as the Manifold Air Temperature (MAT) sensor.

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.

TESTING



See Figure 1

  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



VIN 8 Engine

See Figure 1

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the intake plenum, as outlined in Engine & Engine Overhaul of this repair guide.
  4.  
  5. Detach the electrical connector.
  6.  
  7. Carefully back the sensor out of the plenum.
  8.  



Click image to see an enlarged view

Fig. Fig. 1: On VIN 8 engines, the MAT (or IAT) is mounted in the intake plenum

  1. Installation is the reverse of the removal procedure.
  2.  

VIN J, P and 5 Engines

See Figure 2

  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 from the throttle body extension.
  8.  



Click image to see an enlarged view

Fig. Fig. 2: On most vehicles, the IAT sensor is threaded into the throttle body extension

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

 
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