New Holland UCM 4747 – UCM (Universal Control Module): Left Swash Plate Angle Sensor: In-Range Fault

The sensor monitoring the angle of the left hydrostatic drive pump's swash plate is returning a voltage signal that is within the normal electrical operating range, but the reading is illogical or implausible. The control module compares the drive command sent by the joystick to the actual physical angle of the swash plate; if the sensor reports an angle that does not match the commanded position, the system flags an in-range fault and will typically shut down the drives for safety.

• L213
• L215
• L218
• L220
• L223
• L225
• L228
• L230
• C227
• C232
• C238
• SR130
• SR150

1. 1

   Check hydraulic fluid temperature and condition. Extremely cold fluid or water contamination (milky appearance) can cause sluggish swash plate movement, triggering the code.

2. 2

   Inspect the wiring harness leading to the left swash plate angle sensor for intermittent connection issues on Pin A and Pin B.

3. 3

   Perform live diagnostic monitoring using the machine's display monitor. Observe live sensor feedback while moving the left joystick to check if the reading drops out, spikes, or lags significantly behind the joystick command.

1. 1

   Park the machine on a level surface, lower the boom, shut off the engine, and relieve all hydraulic pressure.

2. 2

   Locate the main hydrostatic drive pump (commonly a Bosch Rexroth unit) and identify the Left Swash Plate Angle Sensor on the pump housing.

3. 3

   Disconnect the electrical connector from the sensor.

4. 4

   Remove the mounting screws securing the sensor.

   Note: OEM parts catalogs state these screws are "NSS" - Not Serviced Separately, so you must retain the original screws or procure replacements locally.

5. 5

   Remove the old sensor.

6. 6

   Install the new sensor and adjust it to obtain a clearance of exactly 3 mm (1/8 in) to the target metal inside the pump.

   Critical Adjustment: The OEM service manual states this exact clearance must be obtained.

7. 7

   Fasten the sensor, reconnect the wiring harness, and clear the UCM codes.

8. 8

   Perform a test drive to ensure the UCM successfully reads the swash plate angle and the machine tracks straight.