Powertrain
generic / SAE
P20E7
Reductant Injection Air Pressure Too High
The DEF system air-assist pressure exceeds the upper threshold — pressure-control valve stuck closed or air pump runaway.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number– / E7
Possible causes
- Pressure control valve stuck closed high
- Air pump does not regulate 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: 120–900 €
- Estimated time: 0.7–3 h
- Component: reductant air pump
- Component: reductant air pressure control valve
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012