The Evaporative Emissions Control System (EVAP) avoids fuel vapors escaping into the atmosphere. These vapors are contained within the EVAP system until the vehicle’s computer determines the time and operating conditions at which the vapors can be purged and cannot any damage to the engine.
The EVAP system consists of the fuel filler cap, the fuel tank, a recent charcoal canister, pressure sensors, valves, and some hoses or vacuum lines. The vapors are stored in the charcoal canister, which is connected to the vent valve. This is usually closed to prevent the vapors from escaping into the atmosphere.
When the diagnostic code P2422 OBD2 is set, it means that the valve is stuck in the closed position. Once it was instructed that it should open, it fails to open due to a malfunction in its control system.