Cannot shift to Park
On pre-facelift W210's tranny gear selector switch is replaceable to like $120 - post-face lift another issue.
I would check electrical is source of the confusion - low voltage on failing battery can be sending gremlins - failing brake light switch gremlins - good time to check./replace Tranny Adapter plug with $14 MB/MOPAR fresh and use 1/2 can of MAF cleaner and pull flood/clean TCM board.... use the other 1/2 can to get into the shifter and spray what you can..
Check tranny fluid level too...
I would use the opportunity to get those relatively low cost items in line.
But that's me
I have a C300, it happens to me now, and I could get it in shift and move, tries many times, left it for hours.
With that been said, have you noticed that if you don't turn your key to on position or step on the brake, the shifter doesn't move? That means there are couple/several electronic component(s) preventing you from shifting. Do we know if it's these sensors that preventing you from shifting? Or is it a mechanical issue like linkage? No. So first thing you should do is to scan your car. If it's electrical, usually something show up. No, it may not turn on CEL. I say it MAY because I just changed my CPS but no CEL or code turned up on the scanner. But I know it was CPS as I replaced it and no more issue. I believe this was one of the few that doesn't show up on the scanner. But it should be few and far in between.
After you scan your car and nothing turn up, next in line should be search, yes, do your own search on the web or in this forum (and many other). We can only give you advises. We can't be responsible and do not solve every problem everyone has. Only after you ran out of options, come here and ask question. Why? because there are so many question that we need to pinpoint your problem and you have the car. You know exactly what's going on with your car. We can't hear any noise your car is/are making. If you describe the noise, then we need to know when it does it, and after that.................. You get the point.
Sorry it got lengthy. But you need to find out if it's electrical or mechanical first.






