New Holland NH 3006 – Engine Control Unit (ECU): Coolant Temperature Signal - ABOVE NORMAL

This code indicates that the voltage signal from the engine coolant temperature sensor is reading higher than the normal operating range, or the reading is illogical when compared to the engine oil temperature sensor. This typically points to an actual engine overheating condition, a failed sensor, or a short circuit in the sensor wiring.

• T5
• T6
• T7
• T8
• TM series
• TM120-TM190
• T6000
• T7000
• Maxxum
• Puma
• Magnum
• Optum
• B90B
• LB75.B
• C185

1. 1

   Verify Coolant Level: Ensure the radiator and coolant reservoir are filled to the proper level.

2. 2

   Check for Physical Overheating: Inspect the radiator for blockages (chaff, dirt), verify the cooling fan is operating correctly, and check the water pump for leaks or failure.

3. 3

   Compare Sensor Readings: Using a diagnostic tool, compare the Engine Coolant Temperature to the Engine Oil Temperature when the tractor is completely cold. Both should read approximately the ambient air temperature. If the coolant sensor reads artificially high while cold, the sensor or wiring is faulty.

4. 4

   Inspect Wiring: Check the wiring harness leading to the coolant temperature sensor for chafing, melted insulation, or a short circuit that could cause a low-voltage/high-temperature false reading.

1. 1

   Cool Down

   Allow the engine to cool completely to avoid severe burns. Slowly remove the radiator cap to relieve any residual cooling system pressure.

2. 2

   Drain Coolant

   Drain a small amount of coolant from the radiator petcock to bring the fluid level below the sensor port, preventing spillage.

3. 3

   Disconnect Wiring

   Locate the coolant temperature sensor on the engine block/thermostat housing and carefully unplug the electrical connector. Inspect the connector pins for corrosion.

4. 4

   Remove Sensor

   Use a deep socket or wrench to unthread the faulty sensor from the housing.

5. 5

   Install New Sensor

   Thread the new OEM coolant temperature sensor into the port. Tighten to the manufacturer's torque specification (do not overtighten, as the brass threads can break).

6. 6

   Reconnect

   Plug the electrical harness back into the new sensor, ensuring the locking tab clicks into place.

7. 7

   Refill and Bleed

   Top off the engine coolant to the correct level. Start the engine with the radiator cap off to bleed any trapped air pockets from the cooling system.

8. 8

   Clear Codes

   Use a diagnostic tool to clear the NH 3006 fault code. Test run the machine under load to ensure the temperature gauge reads accurately and the code does not return.