John Deere 110.15 – ECU: Engine Coolant Temperature High

The controller has detected that the engine coolant temperature has exceeded the normal operating specification threshold (e.g., above 226°F / 108°C). When this code is triggered, the machine will typically initiate an engine derate sequence (limiting power and disabling power boost) to protect the engine from overheating.

• 5085E
• 5090E
• 5090EL
• 5100E
• 5065M
• 5075M
• 5085M
• 5100M
• 5100MH
• 5100ML
• 5115ML
• 5095M
• 5095MH
• 5105M
• 5015ML
• 5090M
• 5115M
• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 5000-series
• 6000-series
• 7000-series
• 7220
• 7320
• 7420
• 8R-series
• 9R-series
• 9570 STS
• 9660 STS
• S-Series
• T-Series
• W-Series
• R4030
• R4038
• R4045
• 329D
• 850K

1. 1

   Immediately reduce engine speed and load to allow the engine to cool

2. 2

   Ensure the engine coolant is at the proper level in the reservoir/radiator. Add coolant if necessary

3. 3

   Check the radiator, cooling fins, and front grilles for debris, dust, or crop buildup. Clean the cooling system thoroughly

4. 4

   Check all coolant lines and hoses for pinches, collapses, or leaks that could restrict coolant flow

5. 5

   Ensure the radiator fill valve (if equipped) is fully closed

6. 6

   Ensure the cooling fan is engaging properly

1. 1

   Cool Down

   Shut off the machine and allow the engine to cool completely to avoid burns from pressurized hot coolant.

2. 2

   Locate the Sensor

   Locate the Engine Coolant Temperature Sensor on the engine block or thermostat housing (location varies by engine model).

3. 3

   Inspect Wiring

   Disconnect the sensor's wiring harness. Inspect the pins for corrosion, moisture, or damage. Check the wiring harness for chafing or shorts back to the ECU.

4. 4

   Test the Sensor

   Use a multimeter to test the resistance of the sensor. If the resistance is out of specification for the ambient temperature (or if the gauge reads hot when the engine is physically cold), the sensor has failed.

5. 5

   Replace the Sensor

   Unthread the old sensor. Quickly thread in the new OEM replacement sensor to minimize coolant loss. Tighten to the manufacturer's torque specification.

6. 6

   Top Off Coolant

   Top off any coolant lost during the sensor swap.

7. 7

   Clear Codes

   Turn the key switch on, clear the stored ECU fault codes via the cab monitor, and run the machine under load to verify the repair.