New Holland UCM 5511 – UCM: Boom Raise/Lower: Implausible State Sensor versus Loader Arm Command, Stuck Spool / Pressure Relief Valve

The control module is sending an electronic command to raise or lower the loader arm (boom), but the spool position sensor on the main control valve is reporting an 'implausible state'. The sensor indicates that the hydraulic spool is not moving to the commanded position.

• L213
• L215
• L218
• L220
• L223
• L225
• L230
• C227
• SR130
• SR150
• SR175
• SV185
• SR200
• TR270

1. 1

   Inspect the loader arm spool sensor wiring harness (specifically the X-22 connector/circuit) for damage, corrosion, or loose connections that could cause an open circuit or short to ground.

2. 2

   Use the New Holland Electronic Service Tool (EST) to monitor the live data of the Loader Arm Spool Sensor. Check if the sensor voltage changes smoothly when the joystick is moved.

3. 3

   Inspect the main control valve to see if the loader arm spool is physically binding or stuck due to debris or scoring.

4. 4

   Verify that the Pressure Relief Valve (PRV) and pilot solenoids are functioning correctly and supplying the required pilot pressure to shift the spool.

1. 1

   Relieve Pressure

   Safely lower the boom to the ground, turn off the engine, and relieve all hydraulic system pressure before servicing the valve block.

2. 2

   Inspect the Spool

   Locate the loader arm section of the main control valve. Remove the end cap and inspect the spool. If the spool is physically stuck, carefully remove it and inspect the bore for scoring, metal shavings, or debris.

3. 3

   Clean or Replace Valve Components

   If debris is found, clean the spool and bore thoroughly. If the spool or valve body is heavily scored, the valve section will need to be replaced.

4. 4

   Test/Replace the PRV

   If the spool moves freely by hand but does not move under hydraulic power, inspect the Pressure Relief Valve (PRV) and the pilot solenoids for the boom circuit. Replace the PRV if it is failing to hold pilot pressure.

5. 5

   Replace the Sensor

   If the spool moves freely and pilot pressure is confirmed to be correct, the loader arm spool sensor is faulty and must be replaced.

6. 6

   Recalibrate

   After replacing the sensor, PRV, or valve components, connect the New Holland Electronic Service Tool (EST) to clear the UCM 5511 code and perform an electro-hydraulic calibration for the loader arm circuit.