I had this problem and the dealer fixed it .. took them a while because they ordered the wrong part the first time .. but mine was the brake booster .. it was a dud from the factory .. and in the process of them fixing it they fucked up my body control module and i had to wait another week on that .. so the first three weeks i had my balt .. it was in the shop for 2 .. good luck tho man

 

UPDATE kinda i have taken it to two different dealers and they said they cant find a problem twith the exhaust so they dont know where else to look.

no light no problem

 

Did they check the exhaust gasket? I had a similar noise that you are describing and it turned out to be my gasket at the header. Burned the edges and it was leaking air. Got it replaced and noise is gone.

 

all they told me was they did the towel in the exhaust and listened for leaks and didnt find anything.