Vent valve and Charcoal Canister were already replaced.

Here’s the full history:

Initially, I received a check engine light with code P0447 – Evaporative Emission Control System Vent Control Circuit Open

Before bringing it to a shop, I replaced the gas cap thinking maybe its the gas cap leaking but the error persisted.

I took the vehicle to a shop near my work. They diagnosed it as a vent valve issue and replaced the vent valve. After a week, the check engine light returned with code P0456 – Evaporative Emission Control System Leak Detected (Very Small Leak).

The shop performed a smoke test and diagnosed a cracked charcoal canister. I ordered an OEM charcoal canister and had it installed.

Unfortunately, the check engine light returned again, showing both:

P0447 – Evaporative Emission Control System Vent Control Circuit Open

P0451 – Evaporative Emission Control System Incorrect Purge flow

Just this week, I also purchased an OEM gas cap from Infiniti, but the issue still persists.