Intake Air Temperature (IAT) Sensor

Intake Air Temperature (IAT) Sensor:

The Intake Air Temperature (IAT) sensor is a thermistor (a resistor which changes value based on temperature) mounted in the intake manifold.

Low temperature produces a high resistance (100,000 ohms at -40°C/-40°F) while high temperature causes low resistance (70 ohms at 130°C/266°F).

The PCM supplies a 5 volt signal through a resistor in the sensor and the PCM then measures the voltage. The voltage will be high when the intake air is cold, and low when the air is hot. By measuring the voltage, the control module knows the intake air temperature.

The PCM uses the IAT signal to control fuel.