Hey folks you have a wet behind the ears newbie here.

I have an 02' Porsche 911 that I recently changed the coolant reservoir on. I drove it for a day and got a CEL. I pulled the codes and found P0491 and P0492 or Secondary Air System. I have checked the electric smog pump and it is working flawlessly. I have looked for fuses and relays but can't find their location. Any assistance would be greatly appreciated.

 

They are at the relay panel behind the left rear seat.
http://www.renntech.org/forums/topic...tion/?p=153232

 

I had these same codes, in my case because I had inadvertently disconnected a vacuum pipe near the dipstick while removing the airbox. The CEL was only illuminated after 40 minutes of driving.
Perhaps your coolant reservoir job resulted in the same issue?

 

Very good point. If you can hear the pump running, vacuum hoses will be the most likely cause of your codes.

 

Thanks for the tip on the relay panel, I'll look there next. I think it's time to buy a Bentley's manual.

Smog pump doesn't come on at start-up, is there a delay on a cold start? The CEL comes on after 30 to 40 minutes.

 

That sounds like an electrical problem, which is good. I'll rather debug that as opposed to tracing vacuum leaks

 

Just a quick update, I checked the 40 amp fuse and found it good. After that I pulled the relay and plugged it back in. Started the car and the smog pump came on, ran for a couple of minutes and shut off. I replaced the relay with a Bosch style 4 pin 40 amp relay and restarted the car. I got the same results. I am going to drive it tomorrow to see if I get another CEL. If i do I'll keep checking, if not I'll keep driving. :-)

 

Sounds like good progress.

 

Did the CEL light come back on??

 

That is the way it is supposed to work.

 

curious if the light came back on after several weeks. on all the fixes I have tried with my cel, it seems to take effect for a few days to weeks, but then comes back again.