Fault Codes/Cummins/2661Cummins2661UnclassifiedGeneralWhat This Code MeansOne or more unacknowledged Engine Shutdown Faults are activePossible Causes•One or More Unacknowledged Engine Fault Codes•Unacknowledged engine faultSuggested Actions1Troubleshoot Engine Fault CodesRelated Cummins Fault Codes266226772632267826292816262828842626288826242891Browse all Cummins fault codes→ASK RUDY ABOUT THIS FAULTGet a diagnosis walkthrough for 2661 on your specific Cummins unit — cited to the OEM manual, not a forum guess.Your question about 2661GET THE ANSWERFree account required — we'll bring your question with you.