Kubota P0116 – Engine Control Unit (ECU) / Engine Control Module (ECM): ECT Higher Than Expected Stage 1

Sets when the Engine Coolant Temperature (ECT) sensor reading exceeds the Stage 1 limit (typically 110 °C / 230 °F) for longer than 30 to 60 seconds while the engine is running, illuminating the MIL and initiating a Power Derate 1.

• WG1605
• WG972
• WG1903
• Toro grounds care equipment
• Genie lifts/telehandlers
• Crown lifts/telehandlers
• Advance/Nilfisk SC8000
• RTV-X900
• RTV-X1120
• RTV-X1140

1. 1

   Check that the radiator has the proper amount of ethylene glycol/water mixture.

2. 2

   Inspect the cooling system (radiator, water pump, and hoses) for cracks and ensure all connections are leak-free.

3. 3

   Ensure there is no trapped air in the cooling path, which can cause localized boiling and false high readings.

4. 4

   Verify that the radiator cooling fan is engaging and operating properly.

5. 5

   Ensure the thermostat is opening at the correct temperature and is not stuck closed.

6. 6

   Inspect the ECT sensor wiring harness for shorts to power, shorts to ground, or open circuits.

1. 1

   Safety First

   Allow the engine to cool down completely. Never open the cooling system or remove sensors while the engine is hot and under pressure.

2. 2

   Locate the Sensor

   Locate the ECT sensor, which is a brass thermistor typically threaded into the engine cylinder head or thermostat housing.

3. 3

   Drain Coolant

   Partially drain the engine coolant below the level of the sensor to prevent a massive spill, or be prepared to swap the sensor very quickly.

4. 4

   Disconnect Wiring

   Unplug the sealed electrical connector from the ECT sensor.

5. 5

   Remove Sensor

   Use a standard spanner/wrench on the hex-head of the sensor to unthread it from the engine block.

6. 6

   Install New Sensor

   Thread the new genuine Kubota ECT sensor into the port. Tighten to the manufacturer's specified torque to ensure the brass threads seal properly without stripping.

7. 7

   Reconnect & Refill

   Reconnect the electrical harness. Refill the radiator with the correct ethylene glycol/water mix.

8. 8

   Bleed the System

   Start the engine with the radiator cap off (or using the designated bleeder valves) to purge any trapped air from the cooling path.

9. 9

   Clear Codes

   Use a diagnostic tool to clear the P0116 / DTC 116 fault code from the ECM. Test run the machine under load to ensure the code does not return.