Pcm Code E037, Shorted Mat Sensor Circuit: Action

PCM turns on SERVICE ENGINE SOON light. PCM substitutes 104°F (40°C) for MAT when coolant temperature is greater than or equal to 104°F (40°C). PCM substitutes coolant temperature for MAT when coolant temperature is less than or equal to 104°F (40°C).

1. With a shorted MAT sensor, PCM parameter ED05 should indicate 148°C or greater. If ED05 does not indicate 148° or greater, sensor is not shorted. See NOTE ON INTERMITTENTS.
2. Checks for sensor short or circuit No. 472 shorted to ground. If PCM parameter EDO5 stays at 142-151°C with sensor unplugged, circuit is shorted to ground.
3. MAT sensors can be damaged by a backfire in intake. If vehicle has had more than one MAT sensor replaced, check for signs of backfire and high intake manifold temperatures due to improper valve train operation.
4. Fault is most likely at PCM connector or PCM. Check for damaged PCM terminals or poor connection before replacing PCM.