New Holland UCM 5273 – UCM: Bucket Rollback / Dump: Solenoids Return Open Circuit

The control module has detected a break in the electrical path on the common return (ground) circuit for the bucket directional valve solenoids. Because the return circuit is open, the solenoids cannot complete their electrical loop, which will result in the electronic bucket rollback and dump hydraulic functions failing to operate.

• 200 Series
• L216
• L218
• L220
• L228
• C175
• C185
• C190

1. 1

   Visually inspect the wiring harness running from the UCM to the loader bucket directional control valve for pinched wires, chafing, or severed lines.

2. 2

   Disconnect the electrical connector at the bucket valve solenoids and inspect the pins (specifically the common return pin 'C') for corrosion, moisture, or pins pushed back into the housing.

3. 3

   Use a multimeter to test the continuity of the common return wire from the solenoid connector back to the UCM harness.

4. 4

   Measure the resistance across the bucket solenoid coils. An infinite resistance (OL) reading indicates the solenoid coil has failed internally.

1. 1

   Safely Prep the Machine

   Lower the loader arms and bucket to the ground (if possible), turn off the ignition, and disconnect the negative battery cable.

2. 2

   Locate the Valve

   Access the loader bucket directional control valve block, typically located under the cab or in the chassis hydraulic compartment.

3. 3

   Address Wiring Issues

   If the diagnostic checks revealed a broken wire or corroded connector on the return circuit, clean the connector with electrical contact cleaner or splice in a new section of wire using weather-sealed connectors.

4. 4

   Replace the Solenoid

   If internally open, unplug the electrical connector from the faulty bucket spool solenoid, remove the retaining nut at the end of the solenoid stem, slide the old solenoid coil off the valve cartridge, slide the new solenoid coil onto the stem and tighten the retaining nut to OEM torque specs.

5. 5

   Reassemble and Test

   Plug the electrical connector back in, reconnect the battery, start the machine, and test the bucket rollback and dump functions to ensure the UCM 5273 code moves to an inactive state or clears.