626 1999-2001

Intake Air Temperature Sensor

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Operation



Specific to:

Mazda 626 1999-2002

The intake air temperature sensor is a variable resistor that is influenced by temperature. Which means, as the temperature changes, so does the resistance inside the sensor. The computer reads this change in resistance to determine the temperature of the incoming air. It uses this reading to determine proper air/fuel mixture and ignition timing settings.

Removal & Installation



Specific to:

Mazda 626 1999-2002

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the IAT sensor from the air cleaner housing or intake air pipe.
  4.  

To install:

  1. Install a new sealing washer to the thermosensor.
  2.  

Testing



Specific to:

Mazda 626 1998-2002

  1. Disconnect the PCM connector.
  2.  
  3. Connect a 104-Pin Breakout Box to the PCM.
  4.  
  5. Tighten the connector bolt to 70-92 inch lbs. (8-10 Nm)
  6.  
  7. Turn the ignition switch to ON.
  8.  
  9. Measure the voltage at PCM terminal 39. Voltage should be approximately 3.1 volts at 68°F (20°C).
  10.  
  11. If not as specified, check the related harness and intake air temperature sensor resistance.
  12.  

Inspection Of Resistance
  1. Remove the intake air temperature sensor.
  2.  
  3. Place the intake air temperature sensor in water with a thermometer, and heat the water gradually.
  4.  
  5. Measure the resistance of the intake air temperature sensor using an ohmmeter.
    1. With water temperature at 68°F (20°C), resistance should be 35.5-39.2 k-ohms.
    2.  
    3. With water temperature at 140°F (60°C, resistance should be 7.18-7.92 k-ohms
    4.  

  6.  
  7. If not as specified, replace the intake air temperature sensor.
  8.  

 
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