New Holland UCM 5504 – UCM: Bucket Rollback / Dump: Sensor Short to Ground / Open Circuit

The control module is not receiving the expected voltage signal from the bucket valve spool position sensor. The system has detected that the sensor's circuit is either broken (open circuit) or the signal wire is shorting directly to the machine's chassis/ground.

• L213
• L215
• L216
• L218
• L220
• L221
• L223
• L225
• L228
• L230
• L234
• C227
• C232
• C238
• L316
• L318
• L320
• SV300

1. 1

   Visually inspect the wiring harness leading to the bucket valve spool sensor for rubbed-through insulation (short to ground) or broken wires (open circuit)

2. 2

   Disconnect the sensor and inspect the connector pins for corrosion, moisture, or pushed-out pins

3. 3

   With the key ON (engine off), check the harness side of the connector for the 5V reference signal and a good ground from the UCM

4. 4

   If the 5V reference and ground are present, check the continuity of the signal wire back to the UCM to ensure it is not broken

1. 1

   Lower the loader arms and rest the bucket flat on the ground to relieve hydraulic pressure.

   Ensure the machine is in a safe state before beginning work.

2. 2

   Turn off the machine and disconnect the negative battery cable.

   Prevents electrical shorts during the repair.

3. 3

   Locate the main loader control valve block.

   This is where the spool sensors are mounted.

4. 4

   Identify the Bucket Valve Spool Sensor.

   It is mounted on the end cap of the bucket spool.

5. 5

   Unplug the electrical connector from the sensor.

   Disconnect the harness to free the sensor.

6. 6

   Unthread/remove the faulty spool position sensor from the valve block.

   Remove the old sensor completely.

7. 7

   Install the new spool position sensor and tighten to OEM specifications.

   Ensure proper seating and torque.

8. 8

   Reconnect the electrical harness.

   Plug the connector back into the new sensor.

9. 9

   Reconnect the battery, turn the key on, and clear the inactive fault codes. Test the bucket rollback and dump functions to verify the repair.

   Validates that the new sensor has resolved the fault.