I have a 2000 S500 that I replaced the brake pads on a few weeks ago, the system was never reset.... the car became hard to get out of park.. thought nothing of it.. then it got much harder... then next time then harder again, the next time very easy for 6-7 parks, now very hard to get out of park... I had a guy look at it who is not super familiar Mercedes but he says it has to be reset by a scanner/computer to allow it to work normally again? Does this make any sense? It doesn't to me because sometimes it works 100% easy and normal, the next time very hard, then the next time, somewhere in the middle... I think it may be the small plastic piece that makes you have to put your foot on the brake to get into gear.. I may tackle this tomorrow, taking out the shifter etc. but did what the guy tell me make any sence? Basically saying the car says the brakes are bad and now as a safety mechanism it won't let me put the car into drive etc.?
Please help, thanks!

No probably just the plastic piece in the shifter assembly

The guy who looked at it was full of crap. It is probably the shifter release mechanism. It is piece that is well known to fail. There are multiple videos available on youtube on how to take that part out and there are threads here with pics on taking it apart.

Git'r done.

Keith