New Holland UCM 4055 – UCM: Hydraulics Enable: Solenoid Supply Open Circuit

The electrical circuit supplying power to the hydraulics enable solenoid is broken, disconnected, or the solenoid coil itself has failed open. When this occurs, the machine will typically lock out the hydraulic functions for safety.

• L213
• L216
• L218
• L220
• L221
• L223
• L225
• L230
• C227
• C232
• C238
• Case SR series
• Case SV series
• Case TR series
• Case TV series

1. 1

   Check UCM unswitched battery fuses, UCM switched fuses, and the Electric Auxiliary Hydraulic On/Off fuses in the engine compartment/fuse panel.

2. 2

   Trace the wiring from the UCM to the hydraulics enable solenoid (often located on the hydraulic pump assembly alongside the park brake solenoid). Look for disconnected plugs, chafed wires, or broken pins.

3. 3

   Disconnect the wires at the hydraulics enable solenoid and use a multimeter to measure the resistance (ohms) across the coil. If the reading is infinite (O.L), the coil is internally open.

4. 4

   Verify that the UCM is sending voltage to the solenoid when the hydraulics enable button is pressed in the cab.

1. 1

   Secure the Machine

   Lower the boom (if possible) or engage the boom lock, turn off the engine, and disconnect the negative battery cable.

2. 2

   Repair Wiring

   If a break or loose connection was found in the harness between the UCM and the solenoid, repair the wire or replace the damaged connector terminal.

3. 3

   Replace the Solenoid

   If the solenoid coil tested open during diagnostics, remove the retaining nut on the solenoid valve stem, slide the old coil off, and install the new coil. Reconnect the harness.

4. 4

   Test the UCM

   If the wiring and solenoid are both in good working order, the UCM itself may have an internal fault preventing it from supplying voltage. Temporarily replace the UCM with a known good unit and retest to confirm.

5. 5

   Clear Codes

   Reconnect the battery, turn the key on, press the hydraulics enable switch, and verify that the fault code clears and hydraulic function is restored.