GM Malibu/Cutlass 1997-2000

Intake Air Temperature (IAT) Sensor

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OPERATION





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Fig. The IAT sensor is located in the air cleaner outlet tube

The Intake Air Temperature (IAT) sensor determines the air temperature inside the intake manifold. Resistance changes in response to the ambient air temperature. The sensor has a negative temperature coefficient. As the temperature of the sensor rises the resistance across the sensor decreases. This provides a signal to the PCM indicating the temperature of the incoming air charge. This sensor helps the PCM to determine spark timing and air/fuel ratio. Information from this sensor is added to the pressure sensor information to calculate the air mass being sent to the cylinders. The IAT is a two wire sensor, a 5-volt reference signal is sent to the sensor and the signal return is based upon the change in the measured resistance due to temperature.

TESTING





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Fig. Measure the resistance across the terminals on the IAT sensor

  1. Turn the ignition switch OFF .
  2.  


NOTE
Inspect sensor connector carefully to make sure it is firmly seated.

  1. Disconnect the wiring harness from the IAT sensor.
  2.  
  3. Measure the resistance between the sensor terminals.
  4.  
  5. Compare the resistance reading with the accompanying chart.
  6.  
  7. If the resistance is not within specification, the IAT may be faulty.
  8.  
  9. Connect the wiring harness to the sensor.
  10.  

REMOVAL & INSTALLATION





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Fig. To remove the IAT sensor, grasp the sensor . . .



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Fig. . . . then gently twist it out of the air cleaner outlet tube

  1. Disconnect the negative battery cable.
  2.  
  3. Detach the connector for the IAT sensor.
  4.  
  5. Carefully twist the IAT sensor out of the air cleaner outlet tube.
  6.  

To install:

  1. Carefully twist the IAT sensor into the air cleaner outlet tube.
  2.  
  3. Attach the connector for the IAT sensor.
  4.  
  5. Connect the negative battery cable.
  6.  

 
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