I have a 2005 Kia Sedona with a Code P2422 reading. How can I fix this problem?

According to Enginetroublecode.com p2422 for every kind of car brand and model : "Evaporative Emissions Control System (EVAP) Vent Valve Stuck Closed"

P2422 Evaporative Emission System Vent Valve Stuck Closed, replace the valve If you have a Hyundai (including Kia), Nissan (including Infinity) or Toyota (including Lexus or Scion) you should disconnect the electrical connector and then apply and remove 12V power to the vent solenoid/valve. The difference between 12V applied and not applied should be the difference between not being able to blow through it and being able to. After testing at least 5 times, if it fails even once, replace the solenoid/valve.

before you go through all that ,, check the gas cap though, with Kia and Hondas,, that code often shows up instead of the P0446 code, which can be solved by re tightening or replacing the gas cap