New Holland ENG 3149 – Engine Control Module (ECM) / EDC7: Coolant Temperature Sensor Test - Failure (Minimum Temperature Not Reached)

The engine is failing to reach its minimum expected operating temperature within a specified timeframe or under specific load conditions. This is almost always caused by a mechanical issue (typically a thermostat that is stuck open) or an electrical issue (the Coolant Temperature Sensor sending an inaccurately low reading).

• T8.xxx Series (e.g., T8.275, T8.300)
• CR9090
• CX8080 Elevation
• CX8090 Elevation

1. 1

   Coolant Level Check: Verify that the coolant level in the radiator and overflow reservoir is correct.

2. 2

   Visual Inspection: Inspect the coolant temperature sensor wiring harness and connector for damage, corrosion, or loose pins.

3. 3

   Temperature Verification: Start the engine and let it run. Use an infrared thermometer or thermal imager to measure the actual temperature at the thermostat housing.

4. 4

   Live Data Comparison: Use a diagnostic scan tool to view the live data for the Coolant Temperature Sensor. Compare the ECU's reading to your infrared thermometer reading to determine if the sensor is faulty or the thermostat is stuck open.

1. 1

   Preparation

   Ensure the engine is completely cool and the cooling system is depressurized before beginning.

2. 2

   Drain coolant (Sensor replacement)

   If replacing the Coolant Temperature Sensor: Drain a small amount of engine coolant so the fluid level drops below the sensor port.

3. 3

   Disconnect harness

   Disconnect the electrical harness from the sensor.

4. 4

   Remove sensor

   Unscrew the faulty sensor from the engine block/thermostat housing.

5. 5

   Install new sensor

   Install the new sensor. (If the new sensor does not have pre-applied thread locker/sealant, apply a liquid thread sealant).

6. 6

   Reconnect harness

   Reconnect the electrical harness.

7. 7

   Drain coolant (Thermostat replacement)

   If replacing the Thermostat: Drain the engine coolant to a level below the thermostat housing.

8. 8

   Remove radiator hose

   Loosen the hose clamp and remove the upper radiator hose from the thermostat housing.

9. 9

   Remove thermostat housing

   Remove the bolts securing the thermostat housing and lift the housing off.

10. 10

    Remove old thermostat

    Remove the old thermostat and scrape away any old gasket material from the mating surfaces.

11. 11

    Install new thermostat

    Install the new thermostat. Ensure it is oriented correctly (the spring side usually faces down into the engine, and the jiggle valve/bleed pin should be positioned at the top).

12. 12

    Install housing

    Install a new gasket/seal and bolt the housing back into place, torquing to OEM specifications.

13. 13

    Reattach radiator hose

    Reattach the radiator hose.

14. 14

    Refill cooling system

    Refill the cooling system with the correct CNH-approved coolant.

15. 15

    Bleed air

    Start the engine with the radiator cap off to bleed air from the cooling system. Top off as necessary.

16. 16

    Clear fault code and test

    Clear the ENG 3149 fault code with a diagnostic tool and test drive the machine under load to ensure it reaches operating temperature.