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

IAT Sensor (Typical):

The Intake Air Temperature (IAT) sensor uses a thermistor to control the signal voltage to the ECM. The variable resistor changes its resistance based on temperature. Low intake air temperature produces high resistance, 100,000 ohms at -40°C (-40°F), while a high temperature causes low resistance, 70 ohms at 130°C (266°F). The ECM supplies a 5.0 volt signal to the IAT sensor through a resistor in the ECM and monitors the voltage change. By monitoring the voltage, the ECM calculates the air temperature and uses this data to assist in determining fuel delivery and spark advance.