Fault Codes/Rehlko/FREQUENCYFAULTRehlkoFREQUENCYFAULTUnclassifiedEmissionsWhat This Code MeansFault shutdown; An X in a red circle on UI screenPossible Causes•Over or under frequencyRelated Rehlko Fault CodesNOECSCF0EEEESTATUS: LOSTDEFAULT PARS WARNINGVOLTAGEFAULTCOOLANTFAULTCOMMUNICATIONSFAULTBATTERYVOLTAGEFAULTFS (1A-T)FUEL PRESS LOW WARNINGFREQUENCY LOW WARNINGBrowse all Rehlko fault codes→ASK RUDY ABOUT THIS FAULTGet a diagnosis walkthrough for FREQUENCYFAULT on your specific Rehlko unit — cited to the OEM manual, not a forum guess.Your question about FREQUENCYFAULTGET THE ANSWERFree account required — we'll bring your question with you.