We have a 2017 with 5,000 miles and the "foghorn" brake issue. After buying it, we found out there has been a technical service bulletin out since 2013. It'* been to the dealership 3 times and still isn't fixed. Even though the dealership said it shouldn't make the noise, Buick and GM say the noise is "normal". Wrong answer! GM refuses to fix it and offered us a $400 maintenance plan for the inconvenience. That'* laughable. At this point, I want a buyback. We've filed a complaint with the better Business Bureau and have already started a Lemon Law case against GM.

Where is the noise coming from? Front or rear? Is it constant or intermittent?

What have they done to try and fix it?

Both front and rear. Low frequency groan when using the brakes that gets worse in wet weather. Sometimes it'* the first stop, sometimes it'* the first several stops. The dealership change the rear pads and it didn't help. The dealership also contacted GM Engineering and GM doesn't have a fix for it. I offered to let the dealership try different brake pads or even some red liquid disc brake quiet but they declined since it wasn't approved by GM.

There is a TSB, where they replace the rear pads, they turn your rear rotors, AND they apply a copper paste between the retainer clips....all three should have been done...

#16-NA-323.....is the TSB

They did all three and it didn't work.

Does this happen all the time, or is it intermittent?

What you should do, is ask them to go for a road test with yours, and create the sound.....then road test a vehicle on the lot, and see if it makes the same noise........

I agree.

When GM says [this is normal] they are attempting to define this behavior as normal for this model of vehicle. Yes, to get out of fixing it, but that'* beside the point. So since they say this is "normal", it is completely appropriate to reply with "Indeed it is? I was not aware of that. Please show me this same behavior on all other cars of this model on the lot." They will either outright refuse, or they will take you for a ride in a few and (likely) they will not have the issue. Either way, your take on this going forward can still be [they could not show me this on any other car] and you can elaborate with [because they refused] or [they attempted on X number of cars and this issue wasn't heard].

Either way, be persistent and reasonable (which it sounds like you already are) and keep the case moving forward.

A thought that would cost a little: Go rent a few of these, collect the VINs as you go, and provided they do not have the issue, you'd have those stats to support you as well. Encores are low-cost on the rental lots these days so the hit shouldn't be too bad.