Fault Codes/Cummins/H389CumminsH389UnclassifiedGeneralWhat This Code MeansEquipment shutdownPossible Causes•Low coolant levelRelated Cummins Fault CodesH669H706H268L028FAIL-TO-SYNCHRONIZE WARNINGOFFE153OVER SPEEDE125RED − FLASHINGE089SERVICE DUEBrowse all Cummins fault codes→ASK RUDY ABOUT THIS FAULTGet a diagnosis walkthrough for H389 on your specific Cummins unit — cited to the OEM manual, not a forum guess.TRY IT FREE