My 2005 Hundai Elantra has check engine code p455 - large leak in the evaporative emmission system. I’ve changed the gas cap (Hundai dealer cap) and the purge valve. Have also examined the charcoal cannister and it’s valve. Both appeared secure and functioning properly. The access panel to the fuel pump appears to be tight. Are there any other “home remedies” that I should try before taking it to the dealer for repair? Thanks, - Turtle8
Since you know where the canister & the purge valve are, did you follow all of the vacuum hoses that lead to and from them? Chances are that you have one disconnected, broken etc. You’d need to follow them all the way to the tank in one direction and to the intake connection in the other.
If you decide to take it to someone you don’t need to take it to a dealer. Any local, independent mechanic should be able to handle this more reasonably.