New Holland UCM 4362 – UCM: Reverse Pump Control Valves (Directional) - Solenoid Right (A) Supply Short to Ground

The control module has detected a short circuit to ground in the power supply circuit for the right-hand reverse directional pump control solenoid, which will likely cause a loss of right-side reverse drive functionality.

• L213
• L215
• L216
• L218
• L220
• L221
• L223
• L225
• L230
• C227
• C232
• C238

1. 1

   Inspect the wiring harness running from the UCM to the right-side hydrostatic drive pump for chafed wires, pinched harnesses, or melted insulation where the supply wire for Solenoid Right (A) might be touching the machine's metal chassis.

2. 2

   Disconnect the electrical connector at the right reverse pump control solenoid and use a multimeter to measure the resistance of the solenoid coil, checking for continuity between the solenoid's supply pin and its metal casing to identify an internal short to ground.

3. 3

   With the solenoid disconnected, turn the key ON and check if the UCM 4362 code changes to an 'Open Circuit' code (UCM 4361 or 4371) to isolate whether the short is in the wiring harness or inside the solenoid itself.

4. 4

   Check the UCM harness connectors for water intrusion, bent pins, or corrosion that could be bridging the solenoid supply pin to a ground pin.

1. 1

   Secure the Machine

   Park the machine on a level surface, lower the boom/bucket to the ground, set the parking brake, and turn off the engine.

2. 2

   Disconnect Power

   Disconnect the negative battery cable to prevent electrical spikes during repair.

3. 3

   Repair the Harness

   If the diagnostic checks revealed a chafed wire in the harness, cut out the damaged section and splice in a new wire using weather-sealed heat-shrink butt connectors. Secure the harness away from moving linkages or hot engine components using zip ties.

4. 4

   Replace the Solenoid

   If the solenoid coil tested as internally shorted, clean the area around the right-side hydrostatic pump to prevent dirt from entering the hydraulic system. Unbolt and remove the faulty reverse directional control solenoid (Solenoid A) and install the replacement. Torque to OEM specifications.

5. 5

   Replace the UCM

   If the wiring and solenoid test perfectly fine, the UCM itself may have an internal short in its driver circuit. Replace the UCM and have a dealer flash/calibrate the new module to the machine.

6. 6

   Test

   Reconnect the battery, clear the stored fault codes, and test the machine's right-side reverse drive function in a safe, open area.