Mitsubishi Galant/Mirage/Diamante 1990-2000

Intake Air Temperature Sensor

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OPERATION





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Fig. The IAT sensor tip is visible when looking into the MAF sensor

The Intake Air Temperature (IAT) sensor determines the air temperature entering 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 receives a 5-volt reference signal and the signal return is based upon the change in the measured resistance due to temperature.

TESTING





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Fig. Testing the resistance of the IAT sensor across the two sensor pins



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Fig. The IAT sensor can be monitored with an appropriate and Data-stream capable scan tool



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Fig. IAT sensor terminal identification-1990-93 Galant



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Fig. IAT sensor terminal identification-2.4L engines



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Fig. Measure the intake air temperature sensor resistance while heating it with a hair drier

  1. Detach the air flow sensor electrical connector.
  2.  
  3. Measure the resistance between terminals No. 4 and No. 6 of the electrical connector, except on the 2.0L DOHC turbo engine.
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  5. If equipped with the 2.0L DOHC turbo engine, measure the resistance between terminals No. 6 and No. 8 of the sensor electric connector.
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  7. Compare test readings to the following specifications:
  8.  

  1. Sensor temperature of 32°F (0°C)-5.3-6.7 kilo-ohms
  2.  
  3. Sensor temperature of 68°F (20°C)-2.3-3.0 kilo-ohms
  4.  
  5. Sensor temperature of 176°F (80°C)-0.30-0.42 kilo-ohms
  6.  

  1. Measure the sensor resistance while heating the sensor area with a hair dryer. As the temperature of the sensor increases, sensor resistance should become smaller.
  2.  
  3. If the measured resistance deviates from the standard value or the resistance remains unchanged, replace the air flow sensor assembly.
  4.  

REMOVAL & INSTALLATION



The IAT sensor is part of the Mass Air Flow (MAF) sensor. The IAT sensor cannot be replaced separately. Refer to MAF sensor removal and installation in this section.

 
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