New Holland UCM 4735 – UCM (Universal Control Module): Right Swash Plate Angle Sensor - Pin B Short to Power

The Universal Control Module (UCM) is detecting an abnormally high voltage on Pin B of the right swash plate angle sensor circuit. A 'Short to Power' means the signal or ground wire (Pin B) is shorted to a 12V or 5V power source, or the sensor has failed internally.

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

1. 1

   Locate the Right Swash Plate Angle Sensor on the right-hand side of the tandem hydrostatic drive pump and visually inspect the wiring harness for chafing, melted insulation, or pinch points.

2. 2

   Disconnect the sensor and inspect the connector pins for corrosion, water ingress, or bent terminals.

3. 3

   Perform a harness voltage test: With the sensor disconnected and the key in the ON position, use a multimeter to probe Pin B on the harness side. If you read 5V or 12V, the harness is shorted to power.

4. 4

   If the harness tests good (no voltage on Pin B when disconnected), the short to power is internal to the swash plate angle sensor itself.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Harness Repair

   If your diagnostic tests revealed a short in the harness, trace the wire from Pin B back to the UCM, locate the short, and repair the damaged wire using heat-shrink butt connectors.

3. 3

   Sensor Replacement

   If the short is internal to the sensor, unplug the electrical connector from the Right Swash Plate Angle Sensor, remove the mounting screws securing the sensor to the hydrostatic pump housing, and install the new swash plate angle sensor. (Note: mounting screws are not supplied with the new sensor and must be reused or procured locally).

4. 4

   Reassembly

   Plug the electrical connector back into the new sensor and reconnect the negative battery cable.

5. 5

   Calibration

   Clear the fault codes using an Electronic Service Tool (EST). Perform the EH Drive / Swash Plate Calibration procedure via the machine's display or EST so the UCM can learn the new sensor's neutral center and maximum stroke limits.