Manifold Air Temperature (MAT) Sensor
The manifold air temperature sensor is mounted in intake manifold downstream of throttle body. See Fig 1 . This sensor measures temperature of air in intake manifold and provides this information to PCM.
The MAT sensor is a thermistor whose resistance changes as a function of temperature. When temperature is low, resistance is high. The resistance decreases as temperature increases. The MAT sensor is a "two wire" sensor with a reference or signal voltage coming from PCM to sensor pin B and a sensor reference ground to sensor on pin A.
The MAT sensor provides intake air temperature information to PCM for use in calculating intake air density. The PCM uses MAT, MAP and rpm to calculate quantity of air flowing into engine. A failure in MAT sensor circuit should set a Code E037 or E038.