Fault Codes/Rehlko/CONCHECKINGRehlkoCONCHECKINGUnclassifiedGeneralWhat This Code MeansPerforming APM connection auto-discoveryPossible Causes•This generator has started in RUN, while the other generator is in OFFRelated Rehlko Fault CodesEMERGENCY STOPESCHKNGMETEREXER NOT SCHBATTERYCHARGERFAULTEXER NOT SCH WBATTERYCHARGER FAULTFAULTAUXFREQUENCY HIGH SD *ALOPFREQUENCY LOW SD *Browse all Rehlko fault codes→ASK RUDY ABOUT THIS FAULTGet a diagnosis walkthrough for CONCHECKING on your specific Rehlko unit — cited to the OEM manual, not a forum guess.Your question about CONCHECKINGGET THE ANSWERFree account required — we'll bring your question with you.