P2421 - EVAPORATIVE EMISSION SYSTEM VENT VALVE STUCK OPEN
POST UPDATED IN January, 2023
Description of DTC code P2421 Generic
The EVAP (Evaporative Emission Control) system retains fuel vapors to prevent them from escaping into the atmosphere. This is done until the PCM determines the conditions and time at which the vapors can be purged and engine damage is prevented.
In this system are the fuel filler cap, fuel tank, charcoal canister, valves, vacuum lines, and pressure sensors. The vapors are stored in the charcoal canister, which is connected to the vent valve, which is usually closed, in order to prevent the vapors from escaping.
The P2421 OBDII fault code setting indicates that the vent valve experienced a lockout condition in the open position.