SheldonYu

I recently just purchased a 2013 c2s and the previous owner installed an AWS switchpath on the car it sounds incredible, especially at high revs. However, it seems like the exhaust valve is stuck open all the time. Even though I love the sound but I would also like to have my "good neighbor" mode as well. I took it to the shop they did a vacuum test on the car and there is no problem and the rod on the valve moved freely. I read a lot of posts about this issue and it seems like it's the problem of COV(change over valve). My question is can the car still pass the vacuum test if the COV goes bad? Thanks!

Joec500

It should still pass vacuum if a COV fails. The COV acts like a splitter routing vacuum from the source to different paths. If the COV fails it's just not routing vacuum to your exhaust valve. The COV is relatively easy to replace.

Here is a good reference

http://plenums.blogspot.com/2016/10/...-overview.html