Fault Codes/Rehlko/FREQUENCY HIGH SD *RehlkoFREQUENCY HIGH SD *UnclassifiedGeneralWhat This Code MeansGoverned frequency exceeds 110% of the system’s frequency setpoint for more than 10 secondsSuggested Actions1Contact an authorized dealer for serviceRelated Rehlko Fault CodesFREQUENCY LOW SD *GENERATOR FREQUENCY HIGH SDFAULTGENERATOR FREQUENCY LOW SDEXER NOT SCH WGENERATOR VOLTAGEL1-L2 HIGH SDEXER NOT SCHGENERATOR VOLTAGEL1-L2 LOW SDESHETEMERGENCY STOPHIGH BATTERY VOLTAGEBrowse all Rehlko fault codes→ASK RUDY ABOUT THIS FAULTGet a diagnosis walkthrough for FREQUENCY HIGH SD * on your specific Rehlko unit — cited to the OEM manual, not a forum guess.TRY IT FREE