Powertrain
generic / SAE
P20A6
Reductant Injection Air Pressure Control Valve Circuit/Open
The drive circuit for the air-assist pressure-control valve in the DEF system is open — atomisation pressure cannot be regulated, dosing accuracy degrades.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number– / A6
Possible causes
- Solenoid winding open high
- Pin pushed back out of connector body low
- Cracked solder joint inside the module or sensor 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: 100–700 €
- Estimated time: 0.7–2.5 h
- Component: reductant air pressure control valve
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012