Air Temperature Sensor ( Ambient / Intake ): Description and Operation

Intake Air Temperature (IAT) Sensor:

The Intake Air Temperature (IAT) sensor is located in the air inlet duct. The IAT sensor is a thermistor (a variable resistor that changes value when the temperature changes). The IAT sensor is connected in series with a fixed resistor in the Powertrain Control Module (PCM). The PCM applies 5 volts to the IAT sensor. The PCM monitors the voltage drop across the IAT sensor and converts the voltage reading into a temperature value. The IAT sensor voltage reading at the PCM will vary with the changes in the intake air temperature.