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Cummins Engines · 434
Power Supply Lost (Unswitched Battery Supply)
What this code means
Power Supply (Unswitched Battery Supply) - Data Erratic, Intermittent, or Incorrect
Applies to: all electronic engines.
Possible causes / checks (from the source)
SPN 627, FMI 2; Lamp: Amber
Need the part?
If diagnosis points to a failed sensor, solenoid, controller or harness part, send us the code (434), machine model and serial number — we quote genuine and OEM replacement parts for export.
Ask for the replacement part on WhatsAppSource: Cummins Engine Fault Code List (Scribd). Single published source — confirm against the manual for your exact model before ordering parts. Compiled 2026-10-30. No manufacturer affiliation.