E037

Code E037:

Sensor Circuit:

DESCRIPTION:

The MAT sensor is a thermistor or variable resistor that varies in resistance with temperature. As the temperature of the sensor increases, sensor resistance decreases. High temperature means low signal voltage. Code E037 sets when the PCM/ECM sees a MAT sensor reading of 148°C when the coolant is less than 100°C. The MAT sensor connector is located on the right rear top of engine behind the alternator.

TEST CONDITIONS:

1. Codes E014, and E015 not set.
2. Coolant sensor less than or equal to 100°C.

FAILURE CONDITIONS:

MAT sensor value greater than or equal to 148°C.

ACTION TAKEN:

1. PCM/ECM turns on "SERVICE ENGINE SOON" telltale.
2. PCM/ECM substitutes 40°C for MAT when coolant is greater than or equal to 40°C.
3. PCM/ECM uses coolant temp for MAT when coolant temp is less than or equal to 40°C.

NOTES ON FAULT TREE:

1. With a shorted sensor, PCM/ECM parameter EDO5 should read 148°C or greater. If not, then the sensor is not shorted, see NOTE ON INTERMITTENTS.

2. Checking for sensor shorted or CKT 472 shorted. If PCM/ECM parameter ED05 stays at 142°C to 151°C with the sensor unplugged, then CKT 472 is shorted to ground.

3. MAT sensors can he damaged by a backfire in the intake manifold. If this vehicle has had more than one MAT sensor replaced, check for signs of backfire or high intake manifold temperatures due to improper valve train operation.

4. Fault is most likely at the PCM/ECM connector or PCM/ECM. Before replacing the PCM/ECM, perform the "PCM/ECM Replacement Check", CHART C-1.

NOTE ON INTERMITTENTS:

Manipulate CKT 472 wiring, the MAT sensor and PCM/ECM connector, while observing PCM/ECM parameter ED05. If the failure is induced, the manifold air temperature will jump from its normal value to the shorted reading of 142°C to 151°C. If wiring and connectors check out OK, substitute a known good MAT sensor and retest.