New Holland UCM 5271 – UCM: Bucket Rollback / Dump: Loader Bucket Solenoid(s) Short to Power

The control module has detected that the electrical circuit supplying or returning from the loader bucket's directional valve solenoid is shorted to a 12V power source. This prevents the module from properly controlling the bucket's rollback and dump functions.

• 200 Series
• 300 Series
• L218
• L220
• L223
• L230
• SR175
• C327
• C332
• C338
• B90B
• B100B
• B115B
• T4 Series
• T4.75
• T4.100
• T4.105
• T4.120

1. 1

   Harness Inspection: Visually inspect the wiring harness running from the UCM to the loader bucket directional control valve for chafed insulation, pinched wires, or melted loom where the solenoid return/supply wire might be rubbing against a 12V power wire.

2. 2

   Voltage Test: Disconnect the harness at the bucket valve solenoid. Turn the key ON (engine off) and use a multimeter to check the solenoid return circuit pins for unexpected voltage. If 12V is present on the ground/return side, the short is in the harness.

3. 3

   Solenoid Test: Check the internal resistance of the bucket valve solenoid using a multimeter to ensure it has not failed internally and shorted out.

4. 4

   Connector Check: Inspect the UCM and solenoid connectors for water intrusion, bent pins, or corrosion that could bridge the power and return circuits.

1. 1

   Disconnect Power

   Turn off the machine and engage the battery disconnect switch (or remove the negative battery cable) to prevent electrical spikes during repair.

2. 2

   Access the Valve Block

   Locate the main hydraulic directional control valve block (usually under the cab or behind the access panels on skid steers/backhoes).

3. 3

   Isolate the Fault

   If the diagnostic checks revealed a harness short, trace the wire back to the UCM. Cut out the damaged section of the wire and splice in a new section using weather-sealed heat-shrink butt connectors.

4. 4

   Replace the Solenoid

   If the harness tests good but the solenoid is internally shorted: Clean the area around the bucket valve, unplug the electrical connector, unscrew the retaining nut, slide the old solenoid off and slide the new OEM solenoid on, then tighten the retaining nut to the specified torque.

5. 5

   Reassemble and Clear Codes

   Reconnect the battery. Turn the key on and use a diagnostic tool (or CAN-bus DTC eraser) to clear the UCM 5271 code from the module's memory. Test the bucket rollback and dump functions for proper operation.