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

Intake Air Temperature Sensor:

PURPOSE
The Intake Air Temperature (IAT) sensor is a thermistor and converts the resistance of the sensor to degrees. IAT is used by the control module to adjust fuel delivery and spark timing according to oncoming air density.

OPERATION
The control module applies a voltage (4-6 volts) signal to the IAT sensor through a resistor within the control module and measures the voltage. By measuring the voltage, the control module can determine IAT. Low intake air temperature produces high resistance (100,000 ohms at -40°C/-40°F) and high voltage. High intake air temperature produces a low resistance (70 ohms at 130°C/266°F) and low voltage.