P2420
EVAP Switching Valve Stuck Closed
The EVAP switching valve cannot open when commanded. Purge or test flow cannot reach the appropriate path and the leak monitor aborts.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Symptoms
- Check engine light on
- Possible smell of fuel near tank or engine bay
- Failed emissions inspection
- Loose-cap warning may appear
Common causes
Ordered by how often each turns out to be the cause.
- Valve stuck closed mechanicallyCommon
- Drive circuit openPossible
- Carbon or debris buildup preventing free movementLess likely
Parts involved
- EVAP Switching Valve
P2420 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.