New Holland UCM 1910 – UCM: Power Supply: Rail 12VH - Loader Plate Interlock and Port Lock Input Power OFF

The control module has detected that the 12-volt power supply rail (Rail 12VH) responsible for powering the Loader Pilot Interlock and Port Lock solenoids has lost power or is turned off, which locks out the loader arms and hydraulic attachments.

• L213
• L215
• L218
• L220
• L221
• L223
• L225
• L228
• L230
• C227
• C232
• C238
• L313
• L315
• L318
• L320
• L323
• L325
• L330
• C327
• C332
• C338
• SR175
• SR220
• SR250
• SV250
• SV300
• TR320
• TV380

1. 1

   Check safety switches (operator seat switch, seat belt switch, and cab door switch) for correct function and physical damage, as these interrupt power to the interlock solenoids

2. 2

   Inspect the main fuse box and relays associated with the UCM and the hydraulic interlock system for blown fuses or faulty relays

3. 3

   Check for related solenoid circuit fault codes (such as 5051, 5052, 5053, 5061, 5062, or 5063) that might pinpoint a short or open circuit

4. 4

   Visually inspect the wiring harness from the UCM to the hydraulic control valve block for chafing, pinched wires, or disconnected plugs, specifically at the X-PORT_LK connector

5. 5

   Verify the UCM has proper battery voltage and a clean ground connection

1. 1

   Secure the Machine

   Park the machine on a level surface, lower the loader arms (or engage the loader arm lock if they must be raised for access), turn off the engine, and engage the parking brake.

2. 2

   Disconnect Power

   Disconnect the negative battery cable (or use the battery disconnect switch if equipped) to prevent electrical shorts during testing.

3. 3

   Access the Hydraulic Control Valve

   Locate the main hydraulic control valve block where the Loader Pilot Interlock and Port Lock solenoids are mounted.

4. 4

   Test the Wiring Continuity

   Disconnect the harness from the interlock solenoids and the UCM. Using a multimeter, test the continuity of the wires on the 12VH rail between the UCM and the solenoids. Repair or replace the wiring harness if you find an open circuit or a short to ground.

5. 5

   Test the Solenoids

   Measure the resistance across the pins of the Loader Pilot Interlock and Port Lock solenoids. If the resistance is out of OEM specification (indicating an internal short or open coil), the solenoid valve must be replaced.

6. 6

   Check for Software Updates

   If the wiring and solenoids test good, the issue may be internal to the UCM. Check with a dealer to see if the machine requires a UCM software update. Service Bulletin 2014-021 notes that UCM software updates resolve various electro-hydraulic control issues and false fault codes.

7. 7

   Reassemble and Clear Codes

   Reconnect all harnesses and the battery. Use the Electronic Service Tool (EST) to clear the UCM 1910 fault code and test the loader functions to ensure the interlock releases properly.