What does code P2421 mean?

Q: What does code P2421 mean?

Evaporative Emission System Vent Valve Stuck Open. P2421 means the powertrain control module (PCM) has detected that the evaporative emission (EVAP) system's vent valve is stuck open when it should be closed, allowing fuel vapor to escape to the atmosphere instead of being captured by the charcoal canister. The PCM typically commands the vent valve closed during a leak test and then monitors the fuel tank pressure sensor; if the tank pressure does not change as expected, the code is set.

DTC codes / P24xx · Auxiliary emission controls / P2421

P2421Evaporative Emission System Vent Valve Stuck Open

P2421 means the powertrain control module (PCM) has detected that the evaporative emission (EVAP) system's vent valve is stuck open when it should be closed, allowing fuel vapor to escape to the atmosphere instead of being captured by the charcoal canister. The PCM typically commands the vent valve closed during a leak test and then monitors the fuel tank pressure sensor; if the tank pressure does not change as expected, the code is set.

SystemPowertrain

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaAuxiliary emission controls

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.