Sensor, Air Temperature, Intake: Operation

The Intake Air Temperature (IAT) sensor is a Negative Temperature Coefficient (NTC) thermistor (resistance varies with temperature). This means at cold air temperature its resistance is high, so the voltage signal will be high. As intake air temperature increases, sensor resistance decreases and the signal voltage will be low. This allows the sensor to provide an analog voltage signal (0.2-4.8 volts) to the Powertrain Control Module (PCM) indicating the density of the air entering the turbo based upon inlet air temperature. The PCM uses this input to calculate injector Pulse Width Modulation (PWM) and adjustment of spark timing to help prevent spark knock with high intake manifold air charge temperatures.