Fault Codes/Rehlko/21256Rehlko21256UnclassifiedGeneralWhat This Code MeansCommunication loss on Global BusRelated Rehlko Fault Codes516281 15516284 1721247516600 320771516600 42007516663 02006516663 312005516666 1Browse all Rehlko fault codes→ASK RUDY ABOUT THIS FAULTGet a diagnosis walkthrough for 21256 on your specific Rehlko unit — cited to the OEM manual, not a forum guess.Your question about 21256GET THE ANSWERFree account required — we'll bring your question with you.