2 times my 05 C240 failed to start after having been drive a while. After waiting 15-20 minutes it started. Took it to my mechanicand he found code of P0341=camsensor performance. He perlaced sensor worked ok twice but then failed. Same code in memory. Further research showed that same code appears for cam and crank sensors and there is no way to tell which. Mecedes says if you chane one you should change the other also. Any thoughts