New Holland UCM 5292 – UCM: Aux Control Function: Solenoid Reverse (B) Supply Short to Ground

The control module has detected that the voltage supply circuit for the Reverse (B) solenoid on the auxiliary hydraulic directional control valve is shorting directly to the machine's ground. This prevents the electrical current from properly energizing the solenoid coil, which disables the auxiliary hydraulics in the reverse direction and can blow system fuses or cause the module to disable the circuit to protect itself.

• L213
• L215
• L216
• L218
• L220
• L221
• L223
• L225
• L228
• L230
• L234
• C227
• C232
• C234
• C237
• C238

1. 1

   Inspect the wiring harness from the UCM to the auxiliary hydraulic control valve block for pinched wires, chafing against the metal chassis, or melted insulation on the supply wire.

2. 2

   Perform a circuit short test by disconnecting the electrical connector at the Reverse (B) solenoid and measuring resistance between the supply wire and machine ground (continuity indicates a shorted harness).

3. 3

   Test the solenoid coil by measuring resistance across its pins and from the supply pin to the metal casing of the valve (continuity to the casing or near-zero resistance indicates an internal short).

4. 4

   Check the UCM and auxiliary hydraulic fuses in the cab fuse panel (e.g., F-028 Electric Auxiliary Hydraulic On/Off Switch fuse) for blown fuses caused by the short.

1. 1

   Safely Park the Machine

   Park on a level surface, lower the loader arms completely (or engage the mechanical boom locks if they must be raised for access), turn off the engine, and disconnect the negative battery cable.

2. 2

   Access the Valve

   Locate the auxiliary hydraulic directional control valve block (typically located under the cab, which may need to be tilted forward for access depending on the model).

3. 3

   Repair the Harness (If Applicable)

   If the diagnostic checks revealed a chafed wire, cut out the damaged section. Splice in a new piece of wire using proper weatherproof crimp connectors or solder, and seal it with heat-shrink tubing. Secure the harness with zip ties away from sharp edges or moving parts.

4. 4

   Replace the Solenoid Coil (If Applicable)

   Disconnect the electrical connector from the faulty Reverse (B) solenoid. Remove the retaining nut located at the end of the solenoid valve stem. Slide the shorted solenoid coil off the valve cartridge. Slide the new OEM solenoid coil onto the cartridge. Reinstall and tighten the retaining nut (do not overtighten, as this can distort the cartridge). Reconnect the electrical connector.

5. 5

   Reassemble and Test

   Reconnect the negative battery cable. Turn the ignition on and use the instrument cluster or Electronic Service Tool (EST) to clear the UCM 5292 fault code. Start the machine and test the auxiliary hydraulic system in both forward and reverse to ensure proper operation.