New Holland UCM 5251 – UCM (Universal Control Module): Loader Bucket Valve (Directional) - Solenoid Rollback (A) Supply Open Circuit

The control module has detected an incomplete electrical path (an open circuit) on the power supply line to the solenoid responsible for the bucket rollback function. Because the circuit is broken, electrical current cannot reach or pass through the solenoid coil, preventing the bucket from rolling back when the operator commands it.

• L213
• L215
• L216
• L218
• L220
• L221
• L223
• L225
• L228
• L230
• L234
• C227
• C232
• C238
• B90B
• B115B

1. 1

   Locate the main hydraulic control valve block and identify the Loader Bucket Directional Valve section. Visually inspect the electrical connector at the Rollback (A) Solenoid for disconnected plugs, corrosion, or pushed-back pins.

2. 2

   Perform a coil resistance test by disconnecting the connector and measuring resistance across the two pins (healthy is ~9 ohms; 'OL' indicates an internal break).

3. 3

   Check harness continuity from the solenoid connector pins back to the corresponding pins on the UCM harness to identify any broken wires.

4. 4

   Perform a voltage supply check at the harness connector with the key on and the operator commanding a rollback function to ensure the UCM is sending the signal.

1. 1

   Safety First

   Lower the loader arms to the ground (if possible) or rest them on mechanical locks. Turn off the ignition and engage the battery disconnect switch to prevent accidental short circuits.

2. 2

   Access the Valve

   Open the cab or access panels to reach the main hydraulic control valve block.

3. 3

   Remove the Faulty Component

   If the diagnostic tests pointed to a failed coil: Disconnect the electrical harness from the Rollback (A) solenoid. Remove the retaining nut at the end of the solenoid stem and slide the faulty coil off the valve cartridge. If the diagnostic tests pointed to a wiring issue: Locate the break or chafe in the harness between the UCM and the valve block. Splice and heat-shrink the broken wire, or replace the damaged connector terminal.

4. 4

   Install the New Part

   Slide the new OEM solenoid coil onto the valve stem and tighten the retaining nut to the manufacturer's torque specification. Reconnect the electrical harness, ensuring the locking tab clicks into place.

5. 5

   Test and Clear

   Turn on the battery disconnect and start the machine. Test the joystick to confirm the bucket rollback function operates smoothly. Use a diagnostic tool or the in-cab display to clear the UCM 5251 fault code.