I have the SCO5RVA in my 2014 MB Sprinter built by Sportsmobile.
I'm getting the 3 chirp "malfunction" alarm despite trying all the troubleshooting (cleaning, reset, etc.).
I couldn't find one then I tried using the number "0", then tried using letter "O". I was able to find one at Lowe's but the price is $13+ more than the SCO5CN model.
Can't see much difference except the the "RV Approved" on the packaging and the addition of some French on the RVA model (First Alert is a Canadian company) on the packaging.
Below are links to the two models at Lowe's:
https://www.lowes.com/pd/First-Alert...-RV/5001687563
https://www.lowes.com/pd/First-Alert...-0-_-78091-_-0