OBD-II code · Powertrain (generic, extended)
P20A5 Reductant Purge Control Valve A Stuck Closed
Reductant purge control valve A is mechanically stuck closed — DEF lines cannot be vented at shutdown, increasing risk of freeze damage in winter.
Is it safe to drive with P20A5?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyValve stuck closed mechanically
- 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
- Best left to a mechanic
- Typical labour
- 0.7–3 h
- Emissions test
- Likely to fail
- Parts involved
- Reductant Purge Valve
Related codes
- P20A0Reductant Purge Control Valve A Circuit/Open
- P24E0Reductant Purge Control Valve B Stuck Closed
- P20A2Reductant Purge Control Valve A Circuit Low
- P20A3Reductant Purge Control Valve A Circuit High
- P20A4Reductant Purge Control Valve A Stuck Open
- P20A6Reductant Injection Air Pressure Control Valve Circuit/Open
- P20A7Reductant Injection Air Pressure Control Valve Performance
- P20A8Reductant Injection Air Pressure Control Valve Circuit Low
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.