Manifold Air Temperature (MAT) Sensor
The manifold air temperature sensor is mounted in intake manifold in front of throttle body. See Fig 1 . This sensor measures temperature of air/fuel mixture in intake manifold and provides this information to ECM.
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 ECM to sensor pin B and a sensor reference ground to sensor on pin A.
The MAT sensor provides intake air temperature information to ECM for use in calculating intake air density. The ECM 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.