Appreciate the feedback

My wife just rolled up and was told me "They aren't sure which part I need. It's either a new ab fluid tank or the valve on the outside. Will show you a picture. later. Code is 46F9-P205C. He said "if you do your own research, don't believe everything you read.""BMW forum isn't always a good thing"

Kinda curious how they can't figure out why they can't figure out what's the root cause.

Is replacing the valve a good thing to try and fix first? Seems like it would be less expensive to start with. what kind of delete are you mentioning? Sorry not familiar. Appreciate the input.
Thanks again.