Pcm Code E37 - 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 uses coolant temperature for MAT when coolant temperature is less than or equal to 104°F (40°C).

1. If MAT sensor is shorted, PCM parameter P.0.5 should indicate 298°F (148°C) or greater. If parameter does not indicate 298°F (148°C), sensor is not shorted. See NOTE ON INTERMITTENTS.
2. Checks for shorted sensor or shorted circuit No. 472. If PCM parameter P.0.5 stays at 288-304°F (142-151°C) with sensor unplugged, short is in circuit No. 472.
3. MAT sensor 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. Before PCM is replaced, perform PFI CHART C-1, PCM REPLACEMENT CHECK.