John Deere 110.04 – ECU (Engine Control Unit): Engine Coolant Temperature Sensor Input Voltage Problem (Voltage Below Normal or Shorted to Low Source)

The engine control module is receiving a voltage signal from the coolant temperature sensor that is too low (typically below 0.1 V). This indicates that the sensor circuit has a short circuit, is grounded out, or the sensor itself has failed internally.

• 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
• 9230
• 9330
• 9430
• 9530
• 9630
• 310SJ
• 444J
• 544J
• 624J
• 130G
• 160GLC
• 210G
• 330LC-8B
• 350GLC
• CTS
• 9560 STS
• 9860 STS

1. 1

   Check the coolant level and ensure the radiator fins are clean (overheating can sometimes accompany sensor failures).

2. 2

   Inspect the sensor wiring harness for any signs of chafing, damage, or a short to ground. Ensure the connector is secure, tight, and free from moisture or corrosion.

3. 3

   Disconnect the coolant temperature sensor pigtail. If the fault code changes from 110.04 (Voltage Low/Short) to 110.03 (Voltage High/Open Circuit), the wiring is likely fine, and the sensor itself is internally shorted.

4. 4

   If the code remains 110.04 with the sensor unplugged, the wiring harness is shorted to ground somewhere between the sensor and the ECU.

5. 5

   Use a multimeter to check the sensor's resistance and compare it to the OEM specifications for your specific engine. If it reads out of range or shows zero resistance (dead short), the sensor is defective.

1. 1

   Power Down

   Turn off the machine and disconnect the battery ground cable to prevent electrical spikes.

2. 2

   Relieve Pressure

   Ensure the engine is completely cool. Slowly remove the radiator cap to relieve any residual cooling system pressure.

3. 3

   Drain Coolant

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

4. 4

   Remove Sensor

   Disconnect the electrical connector from the Engine Coolant Temperature Sensor. Use a deep socket or wrench to unthread the sensor from the engine block/thermostat housing.

5. 5

   Install New Sensor

   Thread the new sensor into the port. (Note: Many OEM sensors come with pre-applied thread sealant or an O-ring; if not, apply a sensor-safe thread sealant). Tighten to the torque specification found in your machine's service manual.

6. 6

   Reassemble

   Reconnect the electrical harness. Refill the coolant to the proper level using John Deere Coolant Conditioner or equivalent.

7. 7

   Clear Codes

   Reconnect the battery, turn the key to the ON position, and use a diagnostic tool or the in-cab monitor to clear the stored 000110.04 fault code. Run the engine and verify the temperature gauge reads correctly and the code does not return.