For what it’s worth I had the exact same code and problem, 11 passenger side buckle switch. What I did to fix it was spray some electronic cleaner, like CRC or something, I used CRC Mass Airflow Cleaner because that’s what I had around. I sprayed it down the buckle (sparingly) and then latched and unlatched the buckle a bunch of times, then let it sit to dry for a while, then cleared the code with the B800. Lights been off and stayed off for at least a month nowMade my first test reading and this is what I got. code 2, then code 11.
I guess there's a problem with my seat belt wire on the passenger side.
I had discovered an unusual amount of freedom back and forth on my drivers seat.
I just received the new bushings and will have a closer look underneath the seat when
I will attempt to install them. I could not move my seat back and forth when someone
mentioned to me to give the electric motor a little tap with a wrench or whatever.
It worked. I could move my seat again. Will keep you posted.