OBD-II code · Powertrain (generic)
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.
Is it safe to drive with P04AB?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyOpen in harness or connector
- PossibleSolenoid winding open
- Less likelyPin pushed back out of connector body
Symptoms
- Check engine light on
- Possible smell of fuel near tank or engine bay
- Failed emissions inspection
- Loose-cap warning may appear
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–1.4 h
- Emissions test
- Likely to fail
- Parts involved
- Evap Purge Valve B, Evap Purge Wiring B
Related codes
- P04A8Exhaust Pressure Control Valve B Position Sensor Circuit Low
- P04A9Exhaust Pressure Control Valve B Position Sensor Circuit High
- P04AAExhaust Pressure Control Valve B Position Sensor Circuit Intermittent or Erratic
- P04ACEVAP System Purge Control Valve B Circuit Low
- P04ADEVAP System Purge Control Valve B Circuit High
- P04AEEVAP System Purge Control Valve B Performance Stuck Open
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.