New Holland UCM 4731 – UCM: Ground Drive: Pin A Short to Ground / Open Circuit

The control module has detected a break in the electrical connection (open circuit) or a short to ground on Pin A of the right swash plate angle sensor's circuit. This prevents the module from determining the actual angle of the swash plate, disabling the ground drive to prevent unintended movement.

• L213
• L215
• L218
• L220
• L223
• L225
• L230
• C227
• C232
• C238

1. 1

   Locate the right swash plate angle sensor underneath the hydrostatic travel pump.

2. 2

   Visually inspect the wiring harness leading to the sensor for chafed wires, pinched lines, or damage caused by debris in the belly pan.

3. 3

   Disconnect the sensor and inspect the pins (specifically Pin A) for corrosion, moisture, or pushed-out pins.

4. 4

   Using a multimeter, test the wire corresponding to Pin A from the sensor connector back to the UCM connector (X-CN2B) for continuity and short to ground.

5. 5

   If the wiring harness tests perfectly, verify if the internal circuitry of the swash plate angle sensor has failed and requires replacement.

1. 1

   Prepare the machine

   Park the machine on a level surface, lower the loader arms completely (or engage the mechanical boom locks if they must be raised for access), and disconnect the negative battery cable.

2. 2

   Access the pump

   Depending on the model, lift the cab or remove the necessary belly/side access panels to reach the hydrostatic tandem pump assembly.

3. 3

   Remove the faulty sensor

   Locate the right swash plate angle sensor on the bottom of the pump. Disconnect the electrical pigtail. Remove the mounting screws holding the sensor to the pump housing. Retain the original mounting screws, as replacement sensors usually do not include them.

4. 4

   Install the new sensor

   Mount the new swash plate angle sensor using the retained screws. Reconnect the electrical harness, ensuring the connector clicks and locks into place.

5. 5

   Reassemble and power up

   Reinstall any removed access panels, lower the cab, and reconnect the battery.

6. 6

   Clear codes and calibrate

   Turn the key on and use the instrument cluster or electronic service tool (EST) to clear the inactive 4731 fault code. Perform a Ground Drive Calibration to sync the new sensor's base voltage with the UCM.