I have a OBD2 reader I can connect to erase. If the CEL comes back on with the same code than I will need to take in. A more advance scan tool than what I have may be required.

 

If the leak is fixed the CEL will go off by itself after a few cold starts.

 

That's what I thought. Obviously its not fixed so it will have to go in the shop. I thought about building or buying a smoke machine to test the evap system from purge line back to the cannister.

 

Did you check the valve under the hood as I suggested in post #5 ?

 

With an evap leak it seems to make sense to just smoke test first, because there so many possibilities.

 

I did replace the purge solenoid as my first attempt to fix this.
I agree with you PulpFriction that a smoke test would be the best way to approach this problem.

 

So, do you blow smoke back into the system from the under hood end of the vapour line?

 

I don’t know, I think you can, into the hose you disconnect from the purge valve. You can introduce the smoke in many places, including at the gas cap. Might need to inject the smoke in more than on place; if you do it at the gas cap, for example, you’ll miss a bad gas cap.

I worry that it will be hard to spot the smoke if the “small leak” is really tiny. Still seems better that replacing a bunch suspected leaky but really perfectly good parts.

 

Does a p0496 point at a particular vent issue? Already replaced the cap but it came back a few days later. It’s a non purge code on a 2006 LT. how fast it resurfaces when cleared is random. Don’t want to just throw money at it but no smoke machine and that code is vague to me other than what system.

 

Usually the valve under the hood, it should be in a closed position, you should not be able the blow air through it, any slight air leakage and it will set a code, I’ve had 2 cheap fake AC Delco valves from Amazon, I got the real deal from RockAuto!

https://www.obd-codes.com/p0496