My service engine light has gone on and off for the last year or so (sometimes I have to turn it off with the code reader) I replaced the purge valve that is toward the back of the engine several months ago. Seemed to fix problem, then light came on again about 3 weeks later. Same code every time (so many I've lost count now) Where are all the components located for this system? Is there any online source for diagrams or schematics? I want to replace everything I can as the car is due to be smogged this summer. The car runs fine, just having the light on constantly is annoying. Thanks