Escalade, Suburban, Tahoe, Yukon, Denali, DenaliXL, YukonXL 1999-2005

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 PCM indicating the temperature of the incoming air charge. This sensor helps the PCM 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. Remove the IAT sensor.
  3. Measure and record the resistance of the IAT sensor 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.

    -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

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