SRX 2004-2005

Intake Air Temperature 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 ECM indicating the temperature of the incoming air charge. This sensor helps the ECM 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.

Removal & Installation

Refer to the MAF sensor removal and installation procedure for the IAT sensors.


  1. Unplug the IAT/MAF sensor connector.

    Click image to see an enlarged view

    Fig. IAT/MAF connector terminal identification

  3. Measure and record the resistance of the IAT sensor at terminals C and D on 3.6L engines or B and E on 4.6L engines at various temperatures, then compare those measurements to the following. The change in resistance should occur smoothly. If there are any sudden changes, the sensor is faulty.

3.6L Engines:

-4°F: 14,096 ohms minimum, 16,827 maximum
14°F: 8,642 ohms minimum, 10,152 maximum
32°F: 5,466 ohms minimum, 6,326 maximum
68°F: 2,351 ohms minimum, 2,649 maximum
77°F: 1,941 ohms minimum, 2,173 maximum
104°F: 1,118 ohms minimum, 1,231 maximum
140°F: 573 ohms minimum, 618 maximum
176°F: 313 ohms minimum, 332 maximum
212°F: 182 ohms minimum, 191 maximum
248°F: 109 ohms minimum, 116 maximum

4.6L Engines

-4°F: 28680 ohms
14°F: 16180 ohms
32°F: 9420 ohms
50°F: 5670 ohms
68°F: 3520 ohms
86°F: 2238 ohms
104°F: 1459 ohms
122°F: 973 ohms
158°F: 467 ohms
194°F: 241 ohms
230°F: 132 ohms
266°F: 77 ohms

  1. If the sensor tests outside of these ranges, replace the sensor.