I have a 2001 S40. In order to pass my emissions test and make the Service Engine light turn off, the mechanic says that the error code indicates replacement of my cam position sensor. I'd rather not spend $270 to replace it. Any advice? And where is it on the engine. Is there a place where I can get decent pictures showing location on line?

 

It is on the back of the engine.
Sorry I don't have any pictures.