Random P0455 gross evap leak/no flow code

[Dave Sherman]

The Traverse has started randomly throwing P0455 codes, usually after showing a tighten fuel cap message. Replaced the suspect aftermarket fuel cap with OEM, and it stayed quiet for a week. Now it's back. I'm thinking the purge valve is next, it's easy to get to. Any ideas? The fuel tank pressure sensor and canister vent solenoid are possible problems too, but involves dropping the gas tank to get to them.

 

[Chris142]

I can't help. I have been chasing that code on my wife's Tahoe forever. Replaced all the valves and such. Had it smoke tested etc. I gave up for now.

 

[khittner]

I've very recently replaced canisters in two of my cars, as well as a vent valve and a vent line filter in my 2010 Hyundai Sonata. These aren't routine wear components, and are most typically damaged, thus generating codes, by overfilling/topping off the tank when fueling the vehicle. If you, like me, have usually tried to get the most out of whatever gasoline bargain that your phone app got you to by squeezing in a few more tenths of a gallon, you'll be money ahead by just stopping your refueling when the gas pump clicks off the first time. $600 later, and I'm getting smarter.

 

[Eddie]

+1 tank top up can be costly.

 

[Dave Sherman]

Thanks, but I don't top off the tank or leave the engine running while fueling. The suspect gas gap must have been installed by the previous owner, and sometimes it wouldn't "click" when I tightened it, which had me wondering. The OEM one was visibly different.