New Holland UCM 1916 – UCM (Universal Control Module): Power Supply: Rail 12VU1 - Right and Left Pumps Forward Input Power OFF

This code indicates that the 12-volt power supply on the "12VU1" rail has been lost or interrupted. This specific electrical rail supplies the input power to the forward directional control solenoids for the right and left hydrostatic drive pumps. When this fault is active, the machine will likely be unable to drive forward.

• L213
• L216
• L218
• L220
• L221
• L223
• L225
• L228
• L230
• L234
• L316
• L318
• L320
• C227
• C232
• C234
• C237
• C238
• C245
• C327
• C332
• C338
• Case CE SR Series
• Case CE SV Series
• Case CE TR Series
• Case CE TV Series

1. 1

   Inspect the main fuse box and the double fuse box for any blown fuses related to the UCM or the EH control system

2. 2

   Inspect the chassis wiring harness that runs from the UCM to the hydrostatic pump solenoids for chafing, pinched wires, or shorts to ground

3. 3

   Disconnect the UCM and the left/right pump forward solenoids, and use a multimeter to check the continuity of the 12VU1 circuit and verify it is not shorted to the chassis ground

4. 4

   Verify system voltage by ensuring the battery is fully charged and the alternator is outputting the correct voltage, as low voltage can trigger UCM power faults

1. 1

   Disconnect Power

   Always disconnect the negative battery cable before servicing the electrical system or welding on the machine to prevent damage to the UCM.

2. 2

   Repair Wiring

   If a short or break was found in the harness during diagnostics, repair the wire using OEM-approved environmental splices, or replace the affected chassis EH wiring harness section.

3. 3

   Replace the UCM

   If the wiring harness, fuses, and external power supplies test good, the fault is likely an internal failure of the UCM's 12VU1 power distribution rail.

4. 4

   Remove the Old UCM

   Disconnect the harness connectors from the UCM and unbolt it from its mounting bracket.

5. 5

   Install the New UCM

   Mount the replacement UCM and securely reconnect the wiring harnesses.

6. 6

   Reprogramming

   Reconnect the battery. A new or remanufactured UCM is shipped blank and must be flashed/programmed with the correct machine software and injector codes using the New Holland Electronic Service Tool (EST) before the machine will operate.