Kubota P3012 – ECU: Low coolant temperature in parked regeneration

This code is triggered during the parked active regeneration mode when the engine warm-up condition is not satisfied. The engine control system detects that the engine coolant temperature is too low to safely or effectively complete the diesel particulate filter (DPF) regeneration process.

• V3800-CR-TE4
• V3307-CR-TE4
• D1803-CR-E4
• 07-CR-E5
• 03-CR Series
• M105
• M108
• M110
• M5140
• M8540
• M9540
• L-Series
• SVL65-2
• SVL75-2
• KX040-4
• U55-4
• Baroness mowers
• Yale forklifts

1. 1

   Check the Coolant Temperature Sensor: Use a diagnostic tool to read live data from the coolant temperature sensor. Verify if the sensor is reading accurately or if there is a short circuit/open circuit in the sensor harness.

2. 2

   Check the Thermostat: If the sensor is reading correctly but the engine is physically failing to reach operating temperature, the thermostat is likely stuck open.

3. 3

   Check the Engine Coolant System: Ensure the coolant level is correct and there are no leaks in the system.

1. 1

   Verify code and monitor data

   Connect a diagnostic scanner to the machine's diagnostic port to verify the P3012 code and monitor live coolant temperature data.

2. 2

   Inspect wiring harness

   Inspect the wiring harness and connector going to the coolant temperature sensor for damage, corrosion, or loose pins.

3. 3

   Replace coolant temperature sensor

   If the live data shows erratic, implausible, or no temperature readings, replace the coolant temperature sensor.

4. 4

   Drain coolant and remove thermostat housing

   If the sensor is functioning properly but the engine will not warm up within the designated timeframe (usually 10 minutes), drain the coolant and remove the thermostat housing.

5. 5

   Inspect and replace thermostat

   Inspect the thermostat. If it is stuck open or opens at a lower temperature than specified (typically 82°C), replace the thermostat.

6. 6

   Reassemble and refill coolant

   Reassemble the housing, refill the system with the correct Kubota-approved engine coolant, and bleed the cooling system of any air.

7. 7

   Clear codes and verify repair

   Clear the fault codes using the diagnostic tool and initiate a manual parked regeneration to verify the repair.