Originally Posted by BMWM.D.
The vacuum pump is what supplies the vacuum needed to operate the wastegate actuators. If the pump isn't putting out what it should (25-30 in. hg), then the wategates might not close as they should.
I've personally never seen an N54 vacuum pump fail, but I guess anything is possible. Testing the vacuum control system is very easy if you know how the system works and what readings to look for.
Thank you for the knowledge on this. I have zero mechanical skills I am going to have to rely on the dealer on this one.
But kind of like you said this is a first I have heard anything like this, and if it has come up on the forums before I have never seen it.
Just hoping it is on the up and up from the dealer and they did not botch a turbo install and say they need to replace something to get there money for labor needed to work on the turbos again.