New Holland UCM 1914 – UCM: Power Supply: Rail 12VS2 - Backup Alarm Input Power OFF

The control module has detected a loss of power, an open circuit, or a short on the 12-volt supply rail specifically dedicated to the backup alarm circuit.

• L213
• L215
• L216
• L218
• L220
• L221
• L223
• L225
• L228
• L230
• L316
• L318
• L320
• C175
• C185
• C190
• C227
• C232
• C238
• SR175
• SR220
• SR250
• SV250

1. 1

   Inspect the main fuse panel for a blown fuse or stuck Backup Alarm Relay.

2. 2

   Inspect the wiring harness from the UCM to the backup alarm relay and backup alarm for chafed wires, shorts to ground, or open circuits.

3. 3

   Verify the UCM ground wire is secure, as a poor ground can cause rail voltage drops.

4. 4

   Disconnect the backup alarm and pressure switch, then use a multimeter to check for continuity and resistance while wiggling the harness to reveal intermittent issues.

1. 1

   Turn off power

   Turn the ignition switch and battery disconnect switch to the OFF position.

2. 2

   Replace fuse or relay

   If the fuse is blown, replace it with the correctly rated fuse. If the backup alarm relay fails testing, remove it from the fuse panel and install a new one.

3. 3

   Repair or replace wiring harness

   If the wiring harness is damaged (shorted to ground or open), repair the damaged section of the wire or replace the affected harness segment.

4. 4

   Replace backup alarm beeper or pressure switch

   If the backup alarm beeper or the pressure switch is internally shorted or failed, unbolt the component, disconnect the weather-pack electrical connector, and install the replacement part.

5. 5

   Erase DTC

   Restore power, turn the ignition ON, and use the diagnostic display or service tool to erase the Diagnostic Trouble Code (DTC).

6. 6

   Verify repair

   Operate the machine in reverse to confirm the backup alarm sounds and verify the fault code does not return.