If you live in an govt over regulated county or state, passing emissions can be a challenge with your VX. I had code p0440 which I thought would be fixed after buying a new gas cap...no luck. I read online that the Evap system runs its self test when you hit half a tank. So to pass, fill up tank and clear code. Drive 100 miles or so, so the system is ready to test but keep adding gas so you don't get close to half a tank. Mine passed emissions using this strategy and the light came back on the next week. I will simply repeat the process each year when inspection is due.