Intake Air Temperature (IAT) Sensor

The two wire manifold IAT sensor is installed in the resonator with the sensor element extending into the air stream. The IAT sensor is a two wire Negative Thermal Coefficient (NTC) sensor. Meaning, as inlet air temperatures increase, resistance in the sensor decreases. As temperature decreases, resistance in the sensor increases. The IAT sensor provides an input voltage to the PCM indicating the density of the air entering the intake manifold based upon intake manifold temperature. At key ON a 5 volt power circuit is supplied to the sensor from the PCM. The sensor is grounded at the PCM through a low-noise sensor-return circuit.

The PCM uses this input to calculate the following:

• Injector pulse-width
• Adjustment of spark timing (to help prevent spark knock with high intake manifold air charge temperatures)