New Holland UCM 5392 – UCM: Enhanced High-Flow Auxiliary Option: EHF Pumps Solenoid(s) Short to Ground

The control module has detected that the electrical circuit for the Enhanced High-Flow (EHF) pump control solenoid—specifically the Proportional Relief Valves (PRVs) that control directional flow—is shorted to ground. This indicates that the voltage supply or return wire for the solenoid is making direct contact with the machine's chassis or a ground source, which will disable the EHF auxiliary hydraulic function and prevent high-flow attachments from operating.

• L223
• L225
• L230
• L234
• L323
• C227
• C232
• C238
• C334

1. 1

   Visually inspect the wiring harness running from the UCM to the EHF pump control valve solenoids for chafing, bare wires, or pinched sections.

2. 2

   Disconnect the EHF pump solenoids and inspect the connector pins for moisture, corrosion, or bent pins that could bridge the circuit to ground.

3. 3

   With the UCM and the solenoid disconnected, use a multimeter to test the supply and return wires in the harness for continuity to chassis ground.

4. 4

   Test the resistance of the EHF pump solenoid coil itself to determine if the coil is internally shorted to its own casing.

1. 1

   Disconnect Power

   Disconnect the machine's battery to prevent electrical damage during the repair.

2. 2

   Resolve Wiring Issues

   If the diagnostic tests revealed a short in the wiring harness, repair the chafed section using appropriate wire repair techniques (solder and heat shrink) or replace the damaged harness section.

3. 3

   Replace the Solenoid

   If the short is internal to the EHF pump control solenoid coil: Locate the EHF pump control valve block. Remove the retaining nut/hardware securing the faulty solenoid coil to the valve stem. Slide the old coil off the valve cartridge. Install the new OEM solenoid coil and torque the retaining nut to specification.

4. 4

   Reassembly

   Reconnect the electrical harness to the solenoid and reconnect the battery.

5. 5

   Clear Codes & Test

   Clear the UCM 5392 fault code using the machine's diagnostic menu or a service tool. Start the machine, engage the Enhanced High-Flow auxiliary hydraulics, and verify proper operation without the code returning.