Pcm Code E37, Shorted Mat Sensor CKT: Description
WARNING: This page is about a different car, the 1992 Cadillac Fleetwood and 1992 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
MAT sensor is a thermistor (temperature sensitive resistor) that varies resistance with changes in temperature. As temperature of sensor increases, resistance decreases. High temperature will result in low signal voltage.
PCM Code E37 sets when PCM sees a MAT sensor reading of 298°F (148°C) when coolant temperature is less than 212°F (100°C). MAT sensor connector is located on right rear top of engine, behind alternator.