Mazda B-Series 1998-06

Intake Air Temperature (IAT) Sensor

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Operation



The Intake Air Temperature (IAT) sensor resistance changes in response to the intake air temperature. The sensor resistance decreases as the surrounding air temperature increases. This provides a signal to the PCM indicating the temperature of the incoming air charge.

Most engines mount the IAT sensor in the air cleaner-to-throttle body supply tube. However, some earlier engines have it mounted to the upper intake manifold.



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Fig. Typical Intake Air Temperature (IAT) sensor

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



  1. Disconnect the negative battery cable.
  2.  



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Fig. To remove the IAT sensor, disconnect the wire harness plug ...

  1. Disengage the wiring harness connector from the IAT sensor.
  2.  
  3. Remove the sensor from the air cleaner outlet tube.
  4.  



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Fig. ... then loosen and remove the sensor from its mounting boss

To install:

  1. Wipe down the IAT sensor mounting boss to clean the sensor area of all dirt and grime.
  2.  
  3. Install the sensor into the air cleaner outlet tube (B Series Pick-up and Navajo) or upper intake manifold assembly securely.
  4.  
  5. Attach the wiring harness connector to the IAT sensor.
  6.  
  7. Connect the negative battery cable.
  8.  

  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



Turn the ignition switch OFF .

  1. Disengage the wiring harness connector from the IAT sensor.
  2.  
  3. Using a Digital Volt-Ohmmeter (DVOM), measure the resistance between the two sensor terminals.
  4.  
  5. Compare the resistance reading with the accompanying chart. If the reading for a given temperature is approximately that shown in the table, the IAT sensor is okay.
  6.  
  7. Attach the wiring harness connector to the sensor.
  8.  



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Fig. IAT sensor specifications chart-MPV models

  1. Disconnect the negative battery cable.
  2.  
  3. Detach the IAT sensor connector.
  4.  
  5. Connect an ohmmeter across the sensor connectors.
  6.  
  7. Measure the resistance of the sensor and compare to the following values:

    77°F (25°C)-29.7-36.3 kohms
     
    185°F (85°C)-3.3-3.7 kohms
     

  8.  
  9. If not as specified, replace the sensor.

    Click image to see an enlarged view

    Fig. Testing Intake Air Temperature Sensor

  10.  

 
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