Powertrain
generic / SAE
P20FB
Reductant Pump B Control Performance/Stuck Off
DEF pump B receives a run command but does not start, or shuts off prematurely.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number– / FB
Possible causes
- Pump head crystallised — motor seized high
- Carbon or debris buildup preventing free movement low
- Component wear with age - mechanical play low
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)
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 150–1100 €
- Estimated time: 1–3.5 h
- Component: reductant pump
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012