Tonight I noticed a humming noise after I parked the car and got out. it is definitely coming from the rear of the car and it sounds like a small electric motor. Everything else seems perfect with the car and I've never noticed this before.

Anyone else ever hear this? Any idea what it could be?

 

Maybe the vacuum pump for the active exhaust valves? Have you pulled the fuse for it (since I've got your back box)?

 

that's what that is.... guess the fuse will come out afterall

 

Fuse was pulled about a week into ownership, about 3 years ago. So I don't think that was it, but I'm not positive (reason why I posted here). That could very well have been the culprit but its not doing it any more so I dont know.