John Deere 110.16 – ECU: Engine Coolant Temperature Moderately High

The engine's coolant temperature has exceeded the normal operating threshold, triggering an initial audible alarm and initiating an Engine Derate Sequence to limit engine power and protect the engine from severe overheating damage.

• 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
• 7220
• 7320
• 7420
• 7520
• 8020 Series
• 9000 Series 4WD
• 329D
• 9860 STS
• 9570 STS
• 644H
• 644H MH
• 750J
• 850J
• 4045TFM
• 6068TFM

1. 1

   Check Coolant Level: Ensure the engine coolant is at the proper level in the expansion tank/radiator.

2. 2

   Inspect the Cooling Package: Check the radiator and oil cooler for physical blockages (dirt, chaff, mud, or debris) that would restrict airflow.

3. 3

   Inspect Coolant Lines: Look for any pinched hoses, collapsed lines, or active coolant leaks.

4. 4

   Check Valves/Strainers: Verify that the radiator fill valve is fully closed. If working on a marine engine, check for a blocked sea water strainer.

5. 5

   Test the Sensor and Wiring: Inspect the Engine Coolant Temperature Sensor (often designated as sensor R13 or B15) and its wiring harness for shorts to ground, open circuits, or damaged pins.

1. 1

   Immediate Action

   Reduce the engine load immediately or stop the engine/tractor to allow the oil and coolant temperatures to cool down safely.

2. 2

   Clean the Radiator

   Use compressed air or a water hose to thoroughly clean the radiator fins and oil cooler of any debris.

3. 3

   Top Off Fluids

   If the coolant level is low, repair any identified leaks and refill the system with approved John Deere coolant.

4. 4

   Replace the Sensor

   If the cooling system is physically sound, full of coolant, and not overheating, but the code remains active, the coolant temperature sensor has likely failed. Disconnect the wiring harness, unthread the old sensor from the thermostat housing/engine block, and install a new sensor.

5. 5

   Clear Codes

   Turn the key switch on, use the diagnostic monitor to clear the stored ECU codes, and run the machine under load to verify the code does not return.