Manufacturer-specific code

This code means different things on different makes. Find yours below.

• Ford

  Battery voltage fault

  On Ford vehicles, U3003 means a module has seen its supply voltage too low or too high; U3003:16 is too low and U3003:17 is too high.

  Likely causes, most likely first

  1. 01weak or old 12V battery (EFB/AGM batteries on start-stop cars)
  2. 02battery replaced without resetting the battery monitoring system
  3. 03loose battery terminals or poor earth
  4. 04alternator overcharging or undercharging
  5. 05car left unused or parasitic drain

  Severity: Caution: get it checked soon · DIY with tools and some experience