It's probably just a coincidence that the ADS light is coming on after the shelf incident. I had the same problem with my S600 a couple years ago. When the interior of the car was warm, as soon as I turned the steering wheel the ADS light came on. It was a faulty steering angle sensor. Replacing that fixed the problem. You really should have the fault codes pulled from the car to see what they tell you. Here's a link to my website that describes ADS...
http://v12uberalles.com/ADS.htm