New Holland UCM 5134 – UCM (Universal Control Module): Right Joystick R-L Axis (ISO/H Pattern) / Bucket Rollback / Dump: Pin B Short to Ground / Open Circuit

The control module has sensed that the Right Joystick Right-Left (R-L) signal has failed low. The fault becomes active when the engine is ON and the voltage on the signal circuit (specifically X-CN3A pin 11) drops below 0.2 Volts.

• L213
• L215
• L218
• L220
• L223
• L225
• L230
• L313
• L316
• L318
• L320
• L321
• L328
• L334
• C227
• C232
• C238
• C327
• C330
• C332
• C334
• C337
• C338
• SR130-SR270
• SV185-SV340
• TR270-TR340
• TV380-TV450

1. 1

   Back-probe the UCM connector (X-CN3A pin 11) with the key ON to verify if the voltage is below 0.2 V and check if it sweeps normally (0.5 V to 4.5 V) when moving the joystick.

2. 2

   Inspect the wiring harness between the right joystick and the UCM for pinch points, chafing, or severed wires.

3. 3

   Disconnect the right joystick and UCM, then test Pin B on the joystick connector to the corresponding UCM pin for an open circuit (infinite resistance).

4. 4

   Test Pin B to the chassis ground to check for a short to ground.

5. 5

   Inspect the joystick and UCM connectors for pushed-out pins, moisture, or corrosion.

1. 1

   Secure the Machine

   Lower the loader arms to the ground, turn off the engine, and disconnect the battery negative terminal to prevent electrical spikes during repair.

2. 2

   Access the Components

   Remove the side console/trim panels to access the right joystick wiring pigtail and the UCM connectors.

3. 3

   Repair Wiring

   If the diagnostic checks revealed a broken wire or a wire shorting against the machine frame, repair the wire using OEM-approved environmental splices, or replace the affected harness section.

4. 4

   Replace the Joystick

   If the harness tests perfectly for continuity and has no shorts to ground, the internal sensor/potentiometer inside the right joystick has failed. Disconnect the joystick pigtail, unbolt the joystick assembly from the console, and install the replacement unit.

5. 5

   Reassemble and Calibrate

   Reconnect the battery and turn the key ON. Clear the inactive UCM 5134 fault code using an Electronic Service Tool (EST) or the machine's display monitor.

6. 6

   Test Operation

   Start the machine and test the bucket rollback and dump functions to ensure the voltage is reading correctly and the fault does not return.