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

Intake Air Temperature Sensor:

PCM Wiring:

Voltage Versus Temperature Chart:

PURPOSE
The Intake Air Temperature (IAT) sensor measures the temperature of the air/fuel mixture in the intake manifold, and sends this information to the PCM. The IAT sensor provides intake air temperature information to the PCM for the use in calculating intake air density. The PCM uses MAT, MAP, and engine speed to calculate the quantity of air flowing into the engine.

OPERATION
The IAT sensor is a thermistor whose resistance changes as a function of temperature. When the temperature is low, the resistance is high. Resistance decreases as the temperature increases. The IAT sensor is a two wire sensor that receives a reference or signal voltage from the PCM.


LOCATION
This sensor is mounted in the intake manifold, in front of the throttle body.

DIAGNOSTIC NOTES
A failure in the IAT sensor circuit should set a code P037 or P038. An intermittent failure can set a code P078.