New Holland UCM 4742 – UCM (Universal Control Module): Left Swash Plate Angle Sensor - Pin A Short to Power

The Universal Control Module (UCM) is detecting an abnormally high voltage on Pin A of the sensor's circuit, meaning the signal wire is shorted to a power source (either the 5V reference or 12V battery power).

• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• 200 Series
• L-Series
• L218
• L220
• L228
• C-Series

1. 1

   Trace the wiring harness from the Left Swash Plate Angle Sensor back to the UCM. Look for rubbed or pinched insulation causing a short to a 12V power wire or 5V sensor supply wire.

2. 2

   Disconnect the sensor and inspect the connector for water intrusion, corrosion, or bent pins that could bridge the power supply pin to the signal pin (Pin A).

3. 3

   With the sensor disconnected and the key ON, use a multimeter to probe Pin A on the harness side. If you read 5V or 12V, the short is in the harness. If voltage is normal, the sensor has failed internally.

1. 1

   Prepare machine for service

   Park the machine on a level surface, lower the boom completely, turn off the engine, and engage the battery disconnect switch to prevent accidental shorting.

2. 2

   Locate the sensor

   Access the hydrostatic drive pump assembly (usually located under the cab). Locate the Left Swash Plate Angle Sensor on the left side of the pump housing.

3. 3

   Remove faulty sensor

   Disconnect the electrical pigtail from the sensor. Remove the mounting screws holding the sensor to the pump housing and pull the sensor out.

4. 4

   Install new sensor

   Insert the replacement swash plate angle sensor into the pump housing. Fasten it using the mounting screws (reuse original hardware or procure standard metric replacements locally).

5. 5

   Reconnect wiring

   Plug the electrical connector back into the new sensor and ensure the locking tab clicks into place.

6. 6

   Calibrate EH drive

   Reconnect the battery. Use the New Holland Electronic Service Tool (EST) to clear the UCM 4742 code and perform an EH drive calibration so the UCM can learn the new sensor's parameters.