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.
Unplug the IAT/MAF sensor connector.
- 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.
- If the sensor tests outside of these ranges, replace the sensor.