[In my reply, I'm *PURPOSELY* going to be a little technical because YOU must be able to *communicate* with the shop personnel.]
In my S500 cpe, I had a *similar* problem in that the same Diagnostic Trouble Code (called 'DTC') would appear. This DTC code 17 says that the CKP (CranKshaft Position) sensor was bad. Same as yours. But if it's bad, the car won't start or run!!!
After lot of investigation, the *REAL* culprit was the Ignition Control Module (ICM)(N1/3). That's where the CKP sensor plugs into. It's located on the driver's side on top of the left fender well, under the protective cover.
To see what it looks like, click here: http://pages.prodigy.net/jforgione/MB_DI.html
The CKP sensor plugs into '2' position on the drawing.
Ask the tech to 'swap' of the ICM module for a trial. And of course, you want $330 applied to *really* fix the problem!