Powertrain
generic / SAE
P201F
Reductant Pump A Stuck On
The DEF (urea) pump A keeps running when commanded off, or its drive current does not drop to zero. Continuous pumping over-pressurises the dosing line and can crystallise DEF at the injector.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number– / 1F
Possible causes
- Pump relay contacts welded high
- Pump driver line shorted to B+ medium
- Carbon or debris buildup preventing free movement 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: 80–600 €
- Estimated time: 0.5–2.5 h
- Component: reductant pump
- Component: reductant pump relay
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012