New Holland UCM 4745 – UCM (Universal Control Module): Left Swash Plate Angle Sensor - Pin B Short to Power

This code indicates that the controller is detecting an abnormally high voltage (a short to a power source) on the Pin B circuit of the sensor that monitors the angle of the left hydrostatic drive pump's swash plate. When this occurs, the machine's safety protocols will typically disable the drive system to prevent unintended movement.

• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• 200 Series
• L213
• L218
• L220
• L228
• C227
• C232
• C238

1. 1

   Locate the left travel pump and inspect the wiring harness leading to the swash plate angle sensor for chafing, pinched wires, or melted insulation that could cause the Pin B wire to short against a 12V power source.

2. 2

   Disconnect the sensor and inspect the plug for water intrusion, corrosion, or bent pins (milky hydraulic fluid or moisture can cause erratic readings).

3. 3

   With the sensor disconnected and the key ON, use a multimeter to check the voltage at Pin B on the harness side. If it reads battery voltage when it shouldn't, the short is in the wiring harness between the UCM and the sensor.

4. 4

   If the harness tests fine, the internal circuitry of the swash plate angle sensor has likely failed and shorted to power.

1. 1

   Preparation

   Park the machine on a level surface, lower the boom, turn off the engine, and engage the parking brake. Disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Access the Pump

   Lift the cab or open the rear access panels as required by your specific model to gain access to the hydrostatic drive pumps.

3. 3

   Remove the Sensor

   Locate the left swash plate angle sensor on the travel pump. Disconnect the electrical pigtail. Remove the mounting screws securing the sensor to the pump housing.

4. 4

   Install the New Sensor

   Place the new sensor into position. (Note: OEM replacement sensors often do not come with new mounting screws; you will need to reuse the original screws or procure them locally). Tighten the screws securely.

5. 5

   Reconnect

   Plug the electrical connector back into the sensor. Ensure the locking tab clicks into place.

6. 6

   Reassemble and Test

   Lower the cab/close panels, reconnect the battery, and turn the key to the ON position. Use the instrument cluster or an electronic service tool (EST) to clear the UCM 4745 fault code.

7. 7

   Calibration

   Start the machine and test the drive system. Depending on the model, a ground drive calibration may need to be performed via the monitor after replacing a swash plate sensor to ensure the UCM learns the new sensor's neutral position.