P04AB
EVAP System Purge Control Valve B Circuit Open
The second EVAP purge control valve (B) - used on systems with a divided purge path or on twin-bank engines - shows an open control circuit. The ECU cannot drive the valve, so vapor cannot be purged through this stage; tank pressure may rise and emissions diagnostics fail.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: easy
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.
- Open in harness or connectorCommon
- Solenoid winding openPossible
- Pin pushed back out of connector bodyLess likely
Parts involved
- EVAP Purge Valve B
- EVAP Purge Wiring B
P04AB 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.