I recently had a knock sensor error showing on my 2018 Chieftain limited. The bike was running like crap. It was in the retard mode, which is a good thing, so as to not damage the engine. I just got the report back from the dealership. The knock sensor wire had melted onto the cylinder head. Obviously this is a horrible location for a wire, near an extrem heat source. Waiting for the new part, will keep you all posted.