Forenza 2007

Intake Air Temperature Sensor

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Operation



Specific to:

Suzuki Forenza 2007-2008

Suzuki Reno 2007-2008

The Intake Air Temperature (IAT) sensor is a thermistor, a resistor which changes value based on the temperature of the air entering the engine. Low temperature produces a high resistance (4,500 ohms at -40 °C [-40 °F]), while high temperature causes a low resistance (70 ohms at 130°C [266 °F]).

The Engine Control Module (ECM) provides 5 volts to the IAT sensor through a resistor in the ECM and measures the change in voltage to determine the IAT. The voltage will be high when the manifold air is cold and low when the air is hot. The ECM knows the intake IAT by measuring the voltage. The IAT sensor is also used to control spark timing when the manifold air is cold. A failure in the IAT sensor circuit sets a diagnostic trouble code P0112 or P0113.

Removal & Installation



Specific to:

Suzuki Forenza 2007-2008

Suzuki Reno 2007-2008

  1. Disconnect the negative battery cable.
  2.  
  3. Disconnect the Intake Air Temperature (IAT) sensor connector.
  4.  
  5. Remove the IAT sensor by pulling it out of the air intake tube.

    Click image to see an enlarged view

    Fig. Intake Air Temperature (IAT) sensor

  6.  
  7. Install the IAT sensor into the air intake tube.
  8.  
  9. Connect the IAT connector.
  10.  
  11. Connect the negative battery cable.
  12.  

Testing



Specific to:

Suzuki Forenza 2007-2008

Suzuki Reno 2007-2008

  1. Observe the IAT sensor scan tool display continuously while performing the tests below.
  2.  
  3. Disconnect the IAT sensor connector.
  4.  
  5. Remove the IAT sensor from the air filter assembly.
  6.  
  7. .Connect the IAT sensor connector to the IAT sensor.
  8.  
  9. Wrap a cool damp shop towel around the IAT sensor in order to lower the temperature while monitoring the IAT sensor parameter on the scan tool
  10.  
  11. A high resistance value should be observed, use Temperature vs. Resistance chart to calculate proper values.
  12.  
  13. If values do not change replace the IAT sensor.
  14.  
  15. Remove the cool shop towel and place a warm damp shop towel around the IAT sensor while monitoring the IAT sensor parameter on the scan tool (low resistance value).
  16.  
  17. A (low resistance value) should be observed,. use Temperature vs. Resistance chart to calculate proper values.
  18.  
  19. If values do not change replace the IAT sensor.

    Click image to see an enlarged view

    Fig. Temperature vs. resistance chart

  20.  

 
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