New Holland UCM 4056 – UCM: Hydraulics Enable: Solenoid Supply Short to Ground

The controller has detected a short circuit to ground in the electrical supply circuit that powers the solenoid responsible for releasing the parking brake and enabling the hydraulic system, causing the machine to lock out the hydraulics and ground drive.

• L213
• L215
• L216
• L218
• L220
• L221
• L223
• L225
• L228
• L230
• L234
• L318
• L320
• C227
• C232
• C238
• SR Series
• SV Series
• TR Series

1. 1

   Check for related active codes (4055, 4057, or 4431). If 4431 is active alongside 4056, resolve 4056 first.

2. 2

   Inspect the fuse panel in the engine compartment. A dead short in the solenoid will often blow the hydraulics enable/park brake fuse.

3. 3

   Inspect the wiring harness between the UCM and the Park Brake Solenoid for chafed insulation rubbing against the chassis, which would cause a direct short to ground.

4. 4

   Ohm test the park brake solenoid by disconnecting it and measuring resistance across the coil pins. A reading of 0 ohms or continuity to the outer casing indicates an internal short.

5. 5

   If the wiring is intact and the solenoid tests fine, check the UCM output pins. If the resistance to ground at the UCM pin is 0 ohms, the UCM has shorted internally and will require replacement.

1. 1

   Secure the Machine

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

2. 2

   Access the Valve

   Raise and safely support the cab to access the hydraulic pump area. Locate the park brake/hydraulics enable valve assembly.

3. 3

   Repair Wiring

   If the diagnostic checks revealed a chafed wire in the harness, splice and heat-shrink the damaged wire, then wrap it in protective loom to prevent future rubbing.

4. 4

   Replace the Solenoid/Valve

   Disconnect the electrical connector from the shorted solenoid. Unscrew the retaining nut holding the solenoid coil to the valve cartridge. Slide the old coil off and install the new OEM coil. (If the entire valve block is damaged, disconnect the hydraulic lines, unbolt the block, and install the new assembly). Torque the retaining nut to OEM specifications.

5. 5

   Reassemble and Test

   Reconnect the battery. Turn the ignition on and press the "Hydraulics Enable" switch on the instrument cluster. Listen for the audible click of the solenoid and verify that the fault code changes from "Active" to "Inactive".

6. 6

   Clear Codes

   Use the Electronic Service Tool (EST) to clear the inactive 4056 code from the UCM's memory.