Powertrain
generic / SAE
P2421
EVAP Vent Valve Stuck Open
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.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number4 / 21
Possible causes
- Vent valve mechanically stuck open high
- Dust/debris preventing valve seat medium
- Carbon or debris buildup preventing free movement low
Symptoms
- Check engine light on
- Possible smell of fuel near tank or engine bay
- Failed emissions inspection
- Loose-cap warning may appear
Inspection / repair
- Difficulty: easy
- DIY: possible
- Estimated cost: 60–250 €
- Estimated time: 0.3–1 h
- Component: evap vent valve
- Component: evap canister
- MIL / check engine light
- emissions-relevant
- drive cycle required
Sources
References
sae:J2012