After replacing my vent valve I was clear for a couple weeks and had just crossed that engine light problem off my list, when of course it returned this morning. Another two-for with a 442 and 455. I replaced most things I know about (see above) and welcome any specific items to check.
PS: bought a used chevy bolt in the fall and its refreshing to have no emissions, oil, transmission, coolant, or brake work.

 

I had to work on it last weekend for an axle seal. I decided to remove the RR wheel well to inspect the filler neck.....they're fine. Some minor surface rust but that's it. rubber hose to tank is fine. all other plastic lines are fine.

I ordered a canister vent valve even though I thought already replaced that but can't be sure...should be here tomorrow. After that I will try the purge solenoid on the engine again. That one I'm sure I replaced 2 years ago for another code.

 

Check the under hood EVAP vent valve, if you can blow air through it, it’s toast, it should be closed until the engine is started.
I got a counterfeit part a few years ago, it failed after two months, I ordered a new AC Delco valve from RockAuto, problem solved.

 

Thanks Oldblue, I did replace the under hood evap solenoid and tested it for the blow thru again before replacing the vent valve at the tank.

 

The rubber gasket on the canister vent valve is always a leak suspect.

 

Thanks for the potential suspect Donbrew. Unfortunately, mine was in fine shape as I lubed it with silicone and even cut the end of the nipple off before removing it, to keep from stretching it.

 

Hey Oldblue,
You mentioned replacing a vapor line to your purge solenoid underhood in order to eliminate a 455 code in a how to thread "fuel line follies". Did that solve the code long-term for you?

 

No more code, so yes it did resolve that code.

 

Do you remember where about the crack was? I cleaned mine and can't see or feel anything....Thanks

 

At the connector fitting