I've searched this in the forum, as well as google... and still no luck.

Car: 2007 e350 (w211) AMG kit package with 120k

The car seems to be stuck in Sport mode. When I push the C/S button, nothing happens. I've tried pushing it while in park, as well as while in Neutral.

There are no warning lights, no check engine light and the car and transmission run great.

Anyone have any ideas??

 

The only noticable thing this button does is that in C the car will start out in second gear, in S it will start out in first gear. Are you certain its not doing that??

 

Well I know that the letter indicator on the dash ("S" or "C") stays in "S" ... So that is the first thing that makes me believe it is not switching.

Also, when accelerating the RPM's seem to be rather high when it finally shifts.

 

... and when I say "rather high" I don't mean abnormal, just more sporty.

 

Some thoughts:
1) Will it let you manually select each gear and display the gear on the display? 1 through 7? If so, that may tend to suggest that the transmission itself is more or less OK.
2) You may be "lucky" and it's just the switch that needs replacing
3) Mercedes transmissions tend to hold in-gear for a long time before changing up, so it may be that you are simply noticing it (reving) more now that you have this other issue