I would be looking for a new dealership if they didn't know what that FSS alert was. Same thing on mine except it was alerting on -667 days not miles when I picked mine up. First day owner and although I wasn't 100% sure what it was I had a pretty good idea. Now I'm not saying I'm smart or anything. I'll leave that up to you guys. However that makes me smarter than that dealer, and that should scare you.