Case IH 3899 – Engine ECU (EDC): Engine temperature exceeded pre-warn level

This code indicates that the engine coolant temperature has risen above the normal operating range and crossed the initial warning threshold, but has not yet reached the critical warning or shutdown level (which triggers code 3900).

• Farmall
• Magnum 180
• Magnum 200
• Magnum 215
• Magnum 220
• Magnum 245
• Magnum 340
• Steiger 335
• Steiger 400
• Steiger 500
• Steiger 600
• Farmall 115U
• Farmall 125A
• MX series
• TG series
• Axial-Flow 2388

1. 1

   Verify the engine coolant level in the reservoir and radiator. Low coolant is a primary cause of overheating.

2. 2

   Inspect the radiator, oil cooler, and condenser package for blockages caused by dirt, chaff, or field debris. Ensure the cooling fan is operating correctly.

3. 3

   Use a diagnostic tool or multimeter to check the live data from the Coolant Temperature Sensor. If the sensor reads an impossibly high temperature when the engine is cold, the sensor or its wiring harness is likely shorted or faulty.

4. 4

   Run the engine and monitor the upper and lower radiator hoses. If the engine is overheating but the radiator remains relatively cool, the thermostat is likely stuck closed.

5. 5

   Check the serpentine/drive belt for proper tension and inspect the water pump for weep-hole leaks or bearing failure.

1. 1

   Locate coolant temperature sensor

   Locate the coolant temperature sensor, typically threaded into the engine block near the thermostat housing or cylinder head coolant passage.

2. 2

   Disconnect sensor harness

   Disconnect the electrical harness connector from the sensor.

3. 3

   Prepare for coolant loss

   Place a catch pan under the engine, as a small amount of coolant will escape.

4. 4

   Replace coolant temperature sensor

   Unscrew the faulty sensor and quickly thread in the new OEM sensor to minimize coolant loss. Torque to the manufacturer's specification.

5. 5

   Reconnect sensor harness

   Reconnect the electrical harness.

6. 6

   Drain engine coolant

   Drain the engine coolant into a clean container (if reusing) by opening the radiator petcock.

7. 7

   Remove upper radiator hose

   Remove the upper radiator hose from the thermostat housing.

8. 8

   Remove thermostat housing cover

   Unbolt and remove the thermostat housing cover.

9. 9

   Remove old thermostat

   Remove the old thermostat and thoroughly clean the mating surfaces of any old gasket material.

10. 10

    Install new thermostat

    Install the new thermostat (ensure the jiggle valve/bleed hole is positioned correctly, usually at the top) and a new gasket/seal.

11. 11

    Reinstall housing cover

    Reinstall the housing cover and tighten the bolts to spec.

12. 12

    Refill cooling system

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

13. 13

    Test and verify repair

    Start the engine, let it reach operating temperature, and check for leaks. Use a diagnostic tool to clear fault code 3899 and verify the temperature remains in the normal range under load.