OBD-II code · Powertrain (generic, extended)
P24DF Reductant Purge Control Valve B Stuck Open
Purge valve B is mechanically stuck open - AdBlue lines drain continuously, dosing pressure cannot build.
Is it safe to drive with P24DF?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyValve stuck open
- Less likelyCarbon or debris buildup preventing free movement
- Less likelyComponent wear with age - mechanical play
Symptoms
- Check engine light or NOx warning on
- AdBlue/DEF level or quality warning
- Possible no-start countdown after ignore period
- Failed emissions inspection (NOx)
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.6–2 h
- Emissions test
- Likely to fail
- Parts involved
- Reductant Purge Valve B
Related codes
- P20A4Reductant Purge Control Valve A Stuck Open
- P24DCReductant Purge Control Valve B Performance
- P24DDReductant Purge Control Valve B Circuit Low
- P24DEReductant Purge Control Valve B Circuit High
- P24E0Reductant Purge Control Valve B Stuck Closed
- P24E1NH3 Sensor Circuit
- P24E2NH3 Sensor Circuit Range or Performance
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.