New Holland UCM 5512 – UCM: Bucket Rollback / Dump: Implausible State Sensor versus Loader Bucket Command

The physical position of the hydraulic spool—as reported by the spool position sensor—does not match the electrical command sent by the operator's joystick. The system expects the spool to be in a specific position based on the input command, but the sensor is reporting a different state. This condition is typically caused by a stuck spool or PRV (Pressure Relief Valve), or a failure of the spool position sensor itself.

• 200 Series
• L213
• L215
• L218
• L220
• L223
• L225
• L230
• C227
• C232
• C238

1. 1

   Check for related electrical codes (such as 5271, 5272, or 5273) for the bucket rollback/dump solenoids before assuming a mechanical failure.

2. 2

   Inspect the wiring harness and connector X-21 going to the Bucket Valve Spool Sensor for corrosion, backed-out pins, or wire chafing.

3. 3

   Verify if the hydraulic spool is physically stuck, which can be caused by cold hydraulic oil or system contamination.

4. 4

   Monitor the spool position sensor voltage/state through the diagnostic menu to verify if it changes smoothly when the spool is commanded to move.

1. 1

   Prepare machine for service

   Safely park the machine on level ground, lower the boom and bucket completely, shut off the engine, and relieve all hydraulic pressure.

2. 2

   Disconnect battery

   Disconnect the negative battery cable to prevent electrical shorts during the repair.

3. 3

   Disconnect sensor wiring

   Locate the EH loader control valve block and disconnect the wiring harness from the bucket valve spool position sensor.

4. 4

   Remove sensor

   Remove the spool position sensor from the control valve.

5. 5

   Inspect and clean valve section

   Inspect the spool and the PRV for physical binding, scoring, or debris. If the spool is stuck, the valve section must be carefully cleaned or replaced to restore free movement.

6. 6

   Replace sensor

   If the spool moves freely but the sensor was reporting an implausible state, install a new EH Loader Control Valve Spool Position Sensor.

7. 7

   Reconnect components

   Reconnect the sensor wiring harness and the battery cable.

8. 8

   Calibrate loader valve

   Turn the key on and perform the 'Loader Valve Calibration' procedure via the instrument cluster/display. (Note: If calibration is not performed, the UCM may throw code 1213: Calibration Functions – Loader Valve Calibration Not Complete).