Powertrain
generic / SAE
P2BA6
NOx Exceedance - SCR NOx Catalyst Performance
NOx emissions are above the legal threshold and the ECU isolates the cause to the SCR NOx catalyst. Conversion efficiency is degraded — aged substrate, sulphur poisoning, or thermal damage.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / numberB / A6
Possible causes
- SCR catalyst substrate aged or contaminated high
- Thermal damage from prior over-temperature event medium
Symptoms
- Check engine light on
- Failed emissions inspection
- Possibly slightly increased fuel consumption
- Sulfur (rotten egg) smell from exhaust under load
Inspection / repair
- Difficulty: hard
- DIY: shop recommended
- Estimated cost: 200–2000 €
- Estimated time: 1–8 h
- Component: scr catalyst
- Component: reductant dosing unit
- MIL / check engine light
- emissions-relevant
- drive cycle required
- limp mode possible
Sources
References
sae:J2012