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

Intake Air Temperature (IAT) Sensor:

DESCRIPTION
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 -4O°C (-4O°F) while high temperature causes low resistance (70 ohms at 130°C (266°F).

OPERATION
The control module supplies a 5 volt signal to the sensor through a resistor in the control module and 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 IAT signal is used by the control module to control fuel.