I have replaced the battery from my car, Mercedes ML350, made in 2003. after which I have got a problem, my radio is blocked and need security code, I tried some, but couldn't fix it. I need your support. Thanks, Karen

Hi

First check through your service documentation for a credit card sized card that may contain the code.

If this is missing the only other way to retrieve the code is:

1) Remove the stereo from the dash and retrieve the serial number stamped on the back of the stereo.

2) Contact your Mercedes dealer with both the serial number and the chassis (VIN no) of your car. You will find the VIN no on your registration document.

The reason you must go through a dealer for this code is that this stereo is secured not only by its serial number but also the actual VIN no. of the vehicle it is installed in. It cannot be 'hacked' through conventional means due to the additional aspect of the VIN number which ties it into the Mercedes Network.

If you do not feel comfortable about removing the stereo - Mercedes will often have a record of the code or if not they will do the work. You should contact them first. There may be a charge for this but unfortunately there is no other way around it.

Hope this has explained the issues involved. Thanks for using FixYa.