LaCrosse 2006-2007

Intake Air Temperature Sensor

Print

Operation



The Intake Air Temperature (IAT) sensor is a variable resistor that measures the temperature of the air entering the engine intake manifold. The Powertrain Control Module (PCM) supplies 5 volts to the IAT signal circuit and a ground for the IAT low reference circuit. When the sensor is cold, the resistance is greater. This results in a greater voltage on the signal circuit that is interpreted by the PCM as a colder IAT. As the sensor becomes warmer, the resistance decreases. This results in a lesser voltage on the IAT signal circuit that is interpreted by the PCM as a warmer IAT. If the PCM detects an IAT sensor signal voltage that is not within a calibrated range of the IAT sensor 1 signal voltage, a DTC is set.

Removal & Installation



3.6L Engine
  1. Turn the ignition OFF.
  2.  
  3. Remove the Intake Air Temperature (IAT)/Mass Air Flow (MAF) electrical connector.
  4.  
  5. Remove the air cleaner intake duct.
  6.  
  7. Remove the IAT/MAF sensor fasteners.
  8.  
  9. Remove the IAT/MAF sensor and the IAT/MAF sensor seal.

    Click image to see an enlarged view

    Fig. Intake Air Temperature (IAT)/Mass Air Flow (MAF) sensor location-3.6L engine

  10.  

To install:

  1. Install the new IAT/MAF sensor seal and the IAT/MAF sensor.
  2.  
  3. Install the IAT/MAF sensor screws. Tighten the IAT/MAF sensor screws to 35 inch lbs. (4 Nm).
  4.  
  5. Install the air cleaner intake duct.
  6.  
  7. Install the IAT/MAF electrical connector.
  8.  

3.8L Engine
  1. Remove the fuel injector sight shield.
    NOTE
    The Intake Air Temperature (IAT) sensor and the Mass Air Flow (MAF) sensor are combined as one sensor.

  2.  
  3. Disconnect the MAF/IAT sensor electrical connector (2).
  4.  
  5. Loosen the air cleaner intake duct clamps.
  6.  
  7. Remove the air cleaner intake duct from the air cleaner housing cover and the throttle body assembly.
  8.  
  9. Remove the MAF/IAT sensor from the air cleaner intake duct.

    Click image to see an enlarged view

    Fig. Intake Air Temperature (IAT)/Mass Air Flow (MAF) sensor location-3.8L engine

  10.  

To install:

  1. Install the MAF/IAT sensor to the air cleaner intake duct.
  2.  
  3. Install the air cleaner intake duct to the air cleaner housing cover and the throttle body assembly.
  4.  
  5. Tighten the air cleaner intake duct clamp screws. Tighten the duct clamps to 27 inch lbs. (3 Nm).
  6.  
  7. Connect the MAF/IAT sensor electrical connector.
  8.  
  9. Install the fuel injector sight shield.
  10.  

Testing



  1. Determine the ambient temperature by using an accurate thermometer.
  2.  
  3. If the ignition has been OFF for 8 hours or more, the Intake Air Temperature (IAT)/Mass Air Flow (MAF) sensor parameter and the Engine Coolant Temperature (ECT) sensor parameter should be within 27°F (15°C) of each other and also the ambient temperature.
  4.  
  5. Turn ON the ignition, and immediately observe the parameters. Compare those sensor parameters to each other and also to the ambient temperature, to determine if the IAT/MAF sensor parameter is skewed.
  6.  
  7. Replace the IAT/MAF sensor, if necessary.
  8.  

 
label.common.footer.alt.autozoneLogo