camshaft sensor
#3
MBWorld Fanatic!
There are 4 of them you need to know which one is bad. Bank 1 or 2 and Intake or Exhaust. I usually just change all of them at once if one goes bad. It's a magnet and if one goes out it's probably time for the rest of them (here or there). 100 bucks for all 4 (Genuine).
Amazon almost 100 bucks for all 4
https://www.amazon.com/Mercedes-Benz-Camshaft-Adjuster-Exhaust-Genuine/dp/B00KB8GM3U/ref=pd_lpo_vtph_263_tr_t_1?_encoding=UTF8&psc=1&refRID=E5NKN2S563C2XK41CSFK&dpID=512g%252BhFptNL&preST=_SY300_QL70_&dpSrc=detail
Video tutorial
Also your car (2011 C300) is a W204 "C-Class (W204)". You'll find better luck visiting the W204 section.
https://mbworld.org/forums/c-class-w204-83/