New Holland ENG 3006 – Engine Control Unit (ECU): Coolant Temperature Sensor - Signal Not Plausible (Compared with Engine Oil Temperature)

The engine's control system is running a plausibility check by comparing the readings of the coolant temperature sensor against the engine oil temperature sensor. If the two readings contradict each other (e.g., the warm-up gradients do not match), the system flags the coolant temperature signal as illogical or not plausible.

• T5.95
• T5.105
• T5.115
• T6 series
• T7 series
• T8 series
• T9 series
• CR9090
• CX8080
• CX8090
• B110
• LB110
• B115
• LB115
• Magnum series (235-340)
• Farmall series
• T6010
• T6020
• T6030
• T6050
• T6070
• TL80A
• TS100A
• JX series

1. 1

   Check coolant levels in the radiator and overflow tank to ensure the sensor is not measuring air instead of liquid.

2. 2

   Test the coolant temperature sensor by disconnecting it and measuring internal resistance with a multimeter; resistance should change smoothly as the engine warms up.

3. 3

   Inspect the wiring harness between the sensor and the ECU for continuity, chafed wires, loose pins, or corrosion.

4. 4

   Test the engine oil temperature sensor, as a faulty oil temperature sensor can trigger this comparative code even if the coolant sensor is fine.

5. 5

   Check the engine thermostat to verify it is not stuck open, which prevents the engine from reaching operating temperature in the expected timeframe.

1. 1

   Prep the Machine

   Turn off the engine, remove the key, and disconnect the battery to prevent electrical shorts. Allow the engine to cool completely.

2. 2

   Locate the Sensor

   Locate the coolant temperature sensor, typically threaded into the engine block near the thermostat housing or water pump.

3. 3

   Drain Coolant

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

4. 4

   Remove the Sensor

   Unplug the electrical harness connector. Use a deep socket or wrench to carefully unthread the faulty sensor from the block.

5. 5

   Install the New Sensor

   Thread the new sensor into the port. (If it does not have pre-applied thread sealant, apply a small amount of liquid thread sealant or Teflon tape). Tighten to the OEM torque specification.

6. 6

   Reconnect

   Plug the electrical harness back into the sensor until it clicks. Reconnect the battery.

7. 7

   Refill and Bleed

   Top off the engine coolant. Start the engine and let it idle with the radiator cap off to bleed any air pockets from the cooling system.

8. 8

   Clear Codes

   Use the CNH EASy diagnostic tool (or a compatible OBD scanner) to clear the ENG 3006 fault code and verify that the live temperature data matches the actual engine temp.