New Holland UCM 5201 – UCM (Universal Control Module): Short to Power, Short to Ground, or Open Circuit on Pin A of the Boom Raise/Lower control circuit

Fault code UCM 5201 indicates a circuit malfunction—specifically a Short to Power, Short to Ground, or Open Circuit—on Pin A of the Boom Raise/Lower control circuit. In New Holland diagnostic literature, this is also explicitly defined as a fault on the Left Joystick (L-R Axis). The system has detected that the electrical signal or voltage on this specific pin is outside the expected operating range, meaning the controller cannot reliably read the operator's input for raising or lowering the boom.

• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• L213
• L218
• L220
• L225
• L230
• C227
• C232
• C238
• L318
• L328
• C327
• C332

1. 1

   Inspect the electrical connector at the base of the Left Joystick and the connectors at the UCM for loose, bent, pushed-back, or corroded pins (specifically Pin A)

2. 2

   Perform a continuity test to check for an open circuit in the wiring harness between the Left Joystick (Pin A) and the corresponding pin on the UCM

3. 3

   Test the Pin A circuit for a short to ground (continuity to chassis ground) or a short to power (voltage present when isolated)

4. 4

   Verify the UCM power supply and ground circuits are operating within limits, as voltage drops can trigger false joystick faults

1. 1

   Safeguard the Machine

   Lower the boom completely to the ground (or engage the mechanical boom lock struts if it must remain raised). Turn off the machine and disconnect the negative battery cable.

2. 2

   Access the Joystick

   Remove the side console/armrest trim to access the base of the Left Joystick.

3. 3

   Clean and Re-seat

   Disconnect the joystick harness. Clean the contacts with electrical contact cleaner and apply dielectric grease. Sometimes, simply re-seating a loose connector resolves the open circuit.

4. 4

   Repair Wiring

   If your multimeter tests revealed a short or open circuit in the harness, trace the harness down to the UCM. Repair any chafed, pinched, or broken wires.

5. 5

   Replace the Joystick

   If the wiring harness tests perfectly between the joystick and the UCM, the fault is likely an internal failure of the Left Joystick's sensors/potentiometers. Replace the Left Joystick assembly.

6. 6

   Reassemble and Test

   Reconnect all harnesses and the battery. Turn the key on and use the instrument cluster or Electronic Service Tool (EST) to clear the inactive fault codes. Test the boom raise/lower function to ensure the code does not return.

7. 7

   UCM Replacement (Worst Case)

   If the code persists after joystick replacement and wiring verification, the UCM itself has suffered an internal fault on that pin's circuit and will require replacement and dealer reprogramming.