Powertrain
generic / SAE
P2BAB
NOx Exceedence — Reagent System Performance
The SCR system has detected that NOx emissions exceed the legal limit and the cause is traced to a performance fault in the reagent dosing system — for example a slow dosing pump, a clogged injector, or a frozen line that is not yet caught by another DTC.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / numberB / AB
Possible causes
- Reductant injector clogged with crystals high
- Dosing pump output below spec medium
- Reagent supply line blocked 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: 200–1500 €
- Estimated time: 1–5 h
- Component: reductant dosing unit
- Component: reductant injector
- Component: reductant pump
- MIL / check engine light
- emissions-relevant
- drive cycle required
- limp mode possible
Sources
References
sae:J2012