Code result
P2421
EVAP Vent Valve Stuck Open
Moderate severity
What it means
The evaporative emission system vent valve does not close on command. The ECU detects that the evap system cannot hold pressure or vacuum because the canister is permanently vented to atmosphere.
Is it safe to drive?
Use caution
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
Vent valve mechanically stuck open
highOne of the most commonly reported causes for this code — check this first.
Dust/debris preventing valve seat
mediumA plausible cause — test and verify before replacing parts.
Carbon or debris buildup preventing free movement
lowLess common, but worth ruling out after the more likely causes.
Related help
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