Hi Guys, new to the forum.
The wife's 2012 Pathfinder with 98k miles on it just started with these 2 codes first was the P0456 (very small leak detected) then eventually the P0442 came too. I first removed the canister and checked for obvious cracks or split hoses etc. The vent control solenoid on the canister seems to be working, it clicks closed with 12v and appears to seal. So I greased the o-ring and re-installed it. A this point I cleared the codes and I replaced the gas cap with a new Nissan OEM cap. Drove for 4 days before the light came back. This time I smoked the system by introducing smoke at the "EVAP Service Port" in the engine bay. With the vent control valve closed I do not see smoke escaping anywhere. I know the smoke is getting to the back because I can see it if I remove the gas cap or open the vent control valve.
What am I missing? I did notice that the plastic clip that holds the vent control valve into the canister is barely effective at keeping it clocked into location, but the sealing is done but the o-ring, not the clip. I don't have a way to check if it maintains pressure in the system but I ran the smoke long enough that I'm reasonable confident that I'd see something it if it was leaking at the time.
I also checked (to the best of my ability) the purge control valve in in the engine bay and it seemed OK. Clicks open with 12v and closed with no power, seems to hold vacuum with a mighty vac.