The intake air temperature (IAT) sensor is a thermistor which changes value based on the
temperature of air entering the engine. A low temperature produces a high resistance (100,000
ohms at -40°C/-40°F), while a high temperature causes a low resistance (70 ohms at
The PCM supplies a 5.0 volt signal to the sensor through a resistor in the PCM and measures
the voltage. The voltage will be high when the incoming air is cold, and low when the air is hot.
By measuring the voltage, the PCM calculates the incoming air temperature. The IAT sensor
signal is used to adjust the spark timing according to the incoming air density.
A common OBD2 computer trouble code is p0113.
|A few related questions and answers
Intake Air Temperature Sensors