Powertrain
generic / SAE
P20E1
Reductant Pressure Too Low
The reductant (AdBlue/DEF) line pressure stays below the demanded value during dosing. The dosing system needs a stable supply pressure to inject metered amounts; without it the system cannot meet NOx targets.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number– / E1
Possible causes
- Reductant pump worn or weak high
- Leak in pressure line medium
- Inline filter clogged medium
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: 250–1500 €
- Estimated time: 1–4 h
- Component: reductant pump
- Component: reductant pressure sensor
- Component: reductant lines
- MIL / check engine light
- emissions-relevant
- drive cycle required
- limp mode possible
Sources
References
sae:J2012