P20EF
Reductant Injection Valve Performance
The SCR reductant injection valve does not deliver the commanded amount of reagent. Causes include clogging by urea crystals, electrical faults or incorrect spray pattern.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: hard
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)
Common causes
Ordered by how often each turns out to be the cause.
- Urea crystals in dosing valveCommon
- Electrical fault in dosing valvePossible
Parts involved
- Def Dosing Valve
- Def Pump
P20EF 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.