E037

Code E037 - Manifold Air Temp. Sensor (High Temp. Indicated):

Temperature To Resistance Values:

Wiring Diagram for Code E037 - Manifold Air Temp. Sensor (High Temp. Indicated):

CODE E037 - MANIFOLD AIR TEMP. SENSOR (HIGH TEMP. INDICATED)

Circuit Description:

The manifold Air Temperature Sensor (MAT) is a thermistor (a resistor which decreases in resistance as temperature increases) mounted in the air cleaner assembly. Low temperature produces a high resistance (100,000 ohms at - 40°C/-40°F) while high temperature causes low resistance (70 ohms at 130°C/266°F)

The ECM supplies a 5-volt signal to the sensor through a resistor in the ECM and monitors this voltage. the voltage will be high when the manifold air is cold, and low when the air is hot. By monitoring the voltage, the ECM knows the manifold air temperature.

Code E037 will set if a signal voltage indicates a manifold air temperature less than about 135°C (275°F) and the vehicle speed is greater than 40 MPH for over 16 seconds.

Possible causes of a Code E037 are:

a. Faulty wiring or terminals
b. CKT 472 shorted to ground
c. A shorted MAT sensor
d. A faulty ECM

Manifold air temperature is one of the inputs used to calculate:

a. Fuel delivery
b. Spark Timing (EST)
c. Knock Control (ESC)
d. Idle (IAC)




Test Description: The following numbered steps correspond with the step numbers on the diagnostic chart.

1. With engine warmed up, MAT should be displayed somewhere between -30°C and 130°C. If not, a MAT circuit fault indicated.

2. With the MAT sensor disconnected, ECM Data ED05 should display a "MAT" reading of below - 30°C. A display below -30°C indicates fault is in the MAT sensor itself. If the "MAT" display is warmer than -30°C, there is a short to ground in the wiring harness or the ECM.




Diagnostic Aids:

An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation.

Check For:

a. Poor Connection or Damaged Harness - Inspect ECM harness connectors for backed out terminals "C11" or "D12", improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection and damaged harness.

b. Intermittent Test - If connections and harness checks out ok, monitor ED05 (MAT) display while moving related connectors and wiring harness. If the failure is induced, the "MAT" display will abruptly change. This will help to isolate the location of the malfunction.



c. Shifted Sensor - The "Temperature To Resistance Value" scale above may be used to test the MAT sensor at various temperature levels to evaluate the possibility of a "shifted" (mis-scaled) sensor which may result in dirveability complaints.