Picked up a 2001 C5 a few days ago. I keep getting a check engine light. Previous owner told me how to reset the code but it keeps coming back. He told me once the car has a few tanks of gas through it problem disappears. I’m on my first full tank of new premium fuel and it’s still coming on. Anyone else having this problem and what did you do to fix it permanently?
As I have been writing, my 2008, 6.2 coupe had the problem in early July. My GM engineeer friend, found it was the emission vent solenoid system. Forum members thought it was code P0449, Champion Motors in Scarborough verified that and replaced the solenoid and a new harness was being recommended by GM, both were done. No problem since. A new gas cap, did not solve that problem.