New Holland UCM 5135 – UCM (Universal Control Module): Right Joystick R-L Axis (ISO/H Pattern) - Pin B Short to Power

The control module has sensed a failure in the Right Joystick's Right-Left (R-L) signal. The fault triggers when the voltage on the signal wire (X-CN3A pin 11) exceeds 4.8 V, causing the machine to default to a Limp Home Implement operating mode.

• 200 Series SSL
• 200 Series CTL
• L218
• L220
• SR175
• B90B
• B100B

1. 1

   Connect the Electronic Service Tool (EST) to the service tool connector, start and operate the machine to verify if fault code 5135 actively records again

2. 2

   Inspect the UCM and the Right Joystick connections to ensure they are secure, tight, and free of corrosion, abrasion, or damage

3. 3

   Inspect the wiring harness running from the UCM to the Right Joystick for any exposed wires that could be shorting to a power source

4. 4

   Probe the signal wire (X-CN3A pin 11) to confirm if the voltage is stuck above 4.8 V

1. 1

   Isolate the Short

   Disconnect the Right Joystick from the harness. Check the voltage on the harness side of Pin B. If the voltage drops to 0V, the short to power is internal to the joystick sensor. If the voltage remains high (above 4.8 V), the short is in the wiring harness between the joystick and the UCM.

2. 2

   Repair the Harness

   If the harness is shorted to a power source, locate the chafed or melted section of the wire and repair/replace the damaged segment.

3. 3

   Replace the Joystick

   If the harness tests fine but the sensor output is internally shorted to power, the Right Joystick assembly has failed and must be replaced.

4. 4

   Replace the UCM

   If the joystick and the wiring harness both test perfectly fine, the UCM has suffered an internal failure and will need to be replaced and reprogrammed.

5. 5

   Clear and Calibrate

   Once the repair is made, use the EST to clear the fault codes. Perform a joystick calibration procedure via the EST to ensure the UCM recognizes the new neutral (2.5 V) and sweep parameters. Test the machine to ensure Limp Home mode is disabled.