New Holland UCM 5141 – UCM: Aux Thumbwheel Axis - Pin A Short to Ground/ Open Circuit

The control module has detected that the electrical circuit for Pin A on the proportional auxiliary thumbwheel (roller switch) has either lost continuity (open circuit) or has shorted directly to the chassis ground. This code has an error priority of 'White', meaning it is not displayed on the standard Instrument Cluster and is only visible via the Electronic Service Tool (EST). While active, the machine's auxiliary hydraulics are automatically disabled for safety.

• L213
• L215
• L216
• L218
• L220
• L223
• L225
• L228
• L230
• L330
• C227
• C232
• C238

1. 1

   Identify the auxiliary thumbwheel located on the Right Joystick

2. 2

   Visually inspect the wiring harness running from the base of the right joystick to the UCM for pinch points, chafing, or exposed wires shorting to the frame

3. 3

   Disconnect the right joystick harness connector and inspect Pin A for corrosion, moisture, bent pins, or pushed-back terminals. Repeat this check at the UCM connector

4. 4

   Check for continuity on the Pin A wire between the joystick connector and the UCM using a multimeter

5. 5

   Check for a short to ground by measuring the resistance between the Pin A wire and a known good chassis ground

6. 6

   If the wiring harness passes continuity and short-to-ground tests, suspect an internal failure (open or short) within the thumbwheel potentiometer itself

1. 1

   Park the machine on a level surface, lower the boom completely, turn off the engine, and disconnect the negative battery cable.

2. 2

   Access the right-hand joystick assembly by removing the necessary side console/armrest trim panels.

3. 3

   Disconnect the electrical connector at the base of the right joystick.

4. 4

   Perform the multimeter diagnostic checks on Pin A as outlined in the diagnostic checks.

5. 5

   If the wiring harness is faulty: Repair the broken wire or splice in a new connector pigtail.

   Ensure the repair is sealed with heat-shrink tubing to prevent moisture ingress.

6. 6

   If the joystick thumbwheel is faulty: Remove the mounting hardware securing the right joystick handle and replace the handle/thumbwheel assembly.

   The proportional roller switch/thumbwheel is often integrated into the handle.

7. 7

   Reconnect the joystick electrical connector and reinstall the armrest trim.

8. 8

   Reconnect the negative battery cable.

9. 9

   Connect the New Holland Electronic Service Tool (EST).

   Clear the inactive 5141 fault code and perform an EH joystick calibration if a new handle was installed.

10. 10

    Start the machine and verify that the auxiliary hydraulics are functioning properly.