I took my car to the dealer for a CEL this morning and they said its the purge valve and that it was replaced under warranty. The lady couldn't give me any details as to what this was. Anyone know?

They also gave me new front pads and rotors under warranty.

 

I can think of two things they might be referring to and both are problematic on our cars.

The fist is the diverter valve. This valve recycles the unused pressurized air that is not put into the engine back into the intake before the turbo. If the valve is leaking, then you would have boost leak and less air in your engine meaning less performance.

The second is the PCV. This valve is the backflow oil pressure valve, and it keeps the pressure of oil constant, by releasing pressure into the valve cover (you might want to read a little more about the PCV on wiki).

It sounds like yours is probably the first though, esp if there wasn't any oil leaking on top of your valve cover.

 

Actually, I spoke with the service tech and he said it has something to do with the emissions system. Apparently it somehow recirculates fuel vapors back into the engine? I'm not sure if this is venting the tank somehow or pulling it from one of the lines.

 

Ah...possibly the EGR valve then.

http://en.wikipedia.org/wiki/EGR_valve

The EGR is another emissions thing that tries to eliminate the amount of raw fuel that one puts out of their exhaust. The problem is they often get clogged up with carbon from the exhaust.

Can I ask how many miles you have on your car and what octane fuel you use?

 

That sounds about what he was saying.

I use 93 octane and I have 27k miles. However, its a 2005.5 and I bought it less then a year ago with 16k miles. I am assuming because the car was flawless and low mileage and a manual that the previous owner would have put in the right fuel, but you never know.