Ditto to James' reply - I too ordered a (relatively) cheap C320 camshaft position sensor
( around $46 with shipping ) that has not arrived yet - I too will check it out.

( EBAY - deutshepartsusa :
MERCEDES Camshaft CAM Position Sensor W140 W129 W210

US $39.49
Shipping:$6.00 Standard Shipping

( this is the same link that James mentions above )

And no, I do not stay up all night - I was paged for a database issue.