John Deere ECU000110.00 – ECU: Engine Coolant Temperature High

The engine coolant temperature has surpassed its normal operating limit (SPN 110, FMI 0). This triggers a warning and causes the Engine Control Unit (ECU) to limit engine power (derate) as a safety measure to prevent damage from overheating.

• 9R
• 9RT
• 9RX
• 310K
• 410L
• 120D
• 210G
• 4044M
• 4044R
• 5045E
• 5055E
• 5075E
• W50
• W70
• 2155
• 2555
• 1165
• 1175
• 318D
• 320E
• 332G
• 4720
• 4930
• 240
• 250
• 260
• 270
• 280

1. 1

   Park the machine on a level surface, shut down the engine, and allow it to cool completely before inspecting the cooling system

2. 2

   Check the coolant level in the radiator and the overflow/recovery tank. Top off with the recommended coolant mixture if low

3. 3

   Inspect the radiator, oil cooler, and other heat exchangers for a buildup of dirt, debris, or obstructions restricting airflow. Clean the radiator fins as necessary

4. 4

   Visually inspect all cooling system hoses, the radiator, and the water pump for any signs of leaks or cracks

5. 5

   Ensure the engine's fan belt has proper tension and is in good condition

6. 6

   Review machine operation to determine if exceptionally heavy loads or high ambient temperatures contributed to overheating

1. 1

   Test coolant temperature sensor

   Disconnect the sensor's electrical connector and inspect for corrosion or damage. Test resistance with a multimeter: it should read 2,200 to 3,000 Ω when cold (approx. 68°F/20°C). Remove and place in hot water (approx. 176°F/80°C); resistance should drop to 250 to 350 Ω. Replace if readings are out of range or do not change.

2. 2

   Inspect and test thermostat

   Drain the cooling system and remove the thermostat housing. Inspect for damage. Place the thermostat in a pot of water and heat it to verify it opens as it approaches its rated temperature. Replace if it remains stuck closed.

3. 3

   Flush cooling system

   If the coolant is old/contaminated or the thermostat was faulty, completely drain the system. Flush with a commercial radiator cleaner and water, run to operating temperature, drain, and rinse with clean water.

4. 4

   Replace parts and refill

   Install the new sensor or thermostat if faulty. Refill the system with a 50/50 mixture of John Deere-recommended ethylene glycol coolant and clean, soft water, plus a coolant conditioner. Run the engine to operating temperature, allow to cool, and re-check the level.