Cutlass L4-138 2.3L VIN A FI HP (1990)
Intake Air Temperature Sensor: Description and Operation
The Manifold Air Temperature sensor (MAT) is a thermistor mounted in the intake manifold. Low intake air temperature produces a high resistance,
while high intake air temperature produces a low resistance. The ECM supplies a 5.0 volt signal to the sensor through a resistor and measures the
voltage. By measuring the voltage, the ECM can determine MAT.