I also had the same problem and code on my 2015 Fun Finder 266KIRB. Under warranty so I took it back to the dealer. They ended up replacing the motor on the side giving the error message. The Hall-effect sensors can fail and I seem to remember another post somewhere where the wiring had broken inside the motor housing. I agree with other posters though. Check all of the connectors on the control box and try to check as much of the wiring as possible between the control box and the slide motor which is reporting the problem. In the end though, you may have to take it to a repair place or find a good mobile tech. Good luck and let us know how you make out.
Ken