Only the dealer or a very high tech indy would have the proper scanner and the brains to use one.

That said, your comment abot the battery going dead is a huge clue. You might have to have the adaptation values reset, because losing battery power on these cars is a big problem. If you didn't disconnect the battery prior to charging it, you may have opened a can of worms. Most battery chargers put out "dirty" voltage that is also much higher than system voltage. This alone, can create havoc with the modules and computers in the car. If the key was in the ignition when you connected or disconnected the battery you could also have caused problems.

Hopefully, all you need is to have the adaptaion values reset by a competent MB shop, though it is a concern that the ARS light is on all the time.