Powertrain
generic / SAE
P04DF
EVAP System Purge Control Valve A Performance Stuck Open
The EVAP purge valve B is mechanically stuck open or its feedback indicates flow even when commanded closed - vapor flows uncontrolled into the intake, disturbing fuel trim and idle quality.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number4 / DF
Possible causes
- Debris on valve seat prevents full closing high
- Return spring weakened 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: 120–350 €
- Estimated time: 0.6–1.5 h
- Component: evap purge valve a
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012