Fault Codes/Generac/503Generac503UnclassifiedGeneralWhat This Code MeansConfiguration MismatchPossible Causes•Voltage configuration set in controller does not match voltage configuration for installed Voltage Configuration Cartridge (VCC).Related Generac Fault Codes504505502505-J45015065001000000325A10051341006Browse all Generac fault codes→ASK RUDY ABOUT THIS FAULTGet a diagnosis walkthrough for 503 on your specific Generac unit — cited to the OEM manual, not a forum guess.TRY IT FREE