When I apply the break, I hear a squeking noise.

The brake noise is usually due to aftermarket brake pads and rotors- the materials are different than Mercedes uses and that causes the noise. The other concern will require a dealer or well equipped shop to diagnose. Good luck!! Greg

I had the same radio happen on my 2002 ML 500 and the technician told me to open my Owener's manuel and look for the card that has a code on it. A radio code. Maybe this will work for you. I also had the brake problem and was told the same thing. It will probably go away eventually as mine did. As long as your brakes are grabbing properly, you should be okay. Good luck! Diane