Case IH 5122 – UCM (Universal Control Module): Right Joystick Forward-Back Axis Pin B Open Or Shorted To Ground Or Power

This code indicates an electrical circuit failure in the right-hand joystick's forward/backward movement sensor. The control module is detecting an abnormal voltage signal on the "Pin B" circuit. This is typically caused by a broken wire (open circuit), a wire rubbing against the machine's chassis (short to ground), a wire touching a voltage source (short to power), or an internal failure of the joystick's position sensor.

• skid steer
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• SR series
• SV series
• TR series
• TV series
• SR175
• SV250
• TR270
• TV380

1. 1

   Visually inspect the wiring harness at the base of the right joystick for pinched wires, chafing, corrosion, or pushed-out pins in the connector.

2. 2

   Check the continuity of the Pin B wire between the joystick connector and the UCM harness connector using a digital multimeter.

3. 3

   Test the Pin B wire for a short to ground (continuity to chassis) and a short to power (voltage on wire with key ON and joystick disconnected).

4. 4

   Verify the internal sensor by monitoring the joystick's voltage output via the machine's diagnostic menu (EST tool) while moving the joystick forward and backward.

1. 1

   Prepare machine for service

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

2. 2

   Remove covers

   Remove the retaining screws and take off the right-hand console or armrest covers to expose the base of the right joystick assembly.

3. 3

   Disconnect joystick

   Disconnect the main electrical connector from the right joystick.

4. 4

   Repair wiring

   If a wiring fault was found during the diagnostic phase, repair the broken wire or replace the damaged section of the harness.

5. 5

   Remove faulty joystick

   If the joystick itself is faulty, remove the mounting bolts securing the joystick base to the armrest bracket.

6. 6

   Install replacement joystick

   Remove the old joystick and install the replacement unit, securing it with the mounting bolts.

7. 7

   Reconnect electrical connector

   Reconnect the electrical connector, ensuring it clicks firmly into place.

8. 8

   Reinstall covers

   Reinstall the console/armrest covers.

9. 9

   Restore power

   Reconnect the battery and turn the key to the ON position.

10. 10

    Clear codes and calibrate

    Clear the fault codes using a diagnostic tool. Note: A joystick calibration procedure may need to be performed via the instrument cluster or EST tool so the UCM can learn the new sensor's neutral, full-forward, and full-backward voltage limits.