2019 GLC Coupe 63 Squeaky Brakes
I am expriencing weird noises as well. I thought it was the brakes, but I narrowed it down to the exhaust button.
Noise appears when you raise rom in neutral to 3.5k and let it go, once it drops below 1k, noise occur.
Happens when applying brakes as well, same mark below 1k rpm.
if I turn off the exhaust button, never hear that noise again
can you see if its related to your button as well?


