P0442 code on 2021 Blazer 3.6l

After a couple years of trouble free motoring, I finally have something to fix. So I have a 2021 Blazer 3.6l with capless fuel tank filler throwing a P0442. Fuel filler flapper seems clean and *looks* OK but have not tested it. I've heard that the purge valve on these 3.6l engines is a common issue.
So...where to start? First, visual check for cracked hoses, fittings, etc., right? Second, I've seen inexpensive smoke machines on Amazon for fifty bucks or so and would be willing to give that a go.
Yeah, I know, it's probably easier and in the end less expensive to have it diagnosed at my go-to mechanic, but I'm pretty bored with nothing to fix under the hood of any of my vehicles.
Also, the purge valve seems to be about $35, which is maybe a buy-one-and-plug-it-in-and-see-if-it-works level of expense.

Advice?

Do you have air? You can charge the system with a few pounds of air and find leaks using a mixture of 10 parts water and 1 part Simple green. Spray and it'll foam where the leak(s) are.

Update: Cleaned the (capless) filler flapper and reset the code...so far the MIL is staying off.
Odd, it appeared squeaky clean before I cleaned it; no residue came off, no dirt, etc. but I guess there could have been enough smutch on there to cause a small leak. Guess we'll see. (Insert crossed fingers emoji here)

Hope it is good now.

Sometimes procrastination works.

...and sometimes it doesn't. Code is back. Guess I'll have to smoke test it.

Smoke tested, found small crack in the charcoal canister. Has anyone ever tried to epoxy a small crack? JB weld perhaps?

JP said:

Smoke tested, found small crack in the charcoal canister. Has anyone ever tried to epoxy a small crack? JB weld perhaps?

Click to expand...

Yes. Tried JB weld. Lasted several months before the code reappeared. Live in Pa, not sure if the cold contributed to the fail. Got me through the inspection though

On second thought, might not have been a crack, just vapor coming out the canister vent.
Might be a moot point, as the MIL has gone off and stayed off since I deleted the trouble code.

Now that I've said that...I'm guessing it will come back on in the middle of winter.

Yeah...the code is back. Ordered a new part and will replace it over the weekend.