Inlet Air Temperature (IAT) Sensor

The inlet air temperature sensor is similar in construction to the coolant temperature sensor. Sensor is mounted in the air cleaner body, near inlet duct. See Figure. As air temperature rises, the resistance of the sensing thermistor decreases.

The ECA applies a 9-volt reference voltage to sensor and monitors the resultant voltage drop across sensor. By this method, the ECA can determine proper spark advance and Thermactor air injection flow. At high inlet temperatures (above 90°F), the ECA will modify timing advance as necessary to prevent spark knock.