OBD-II code · Powertrain (generic, extended)
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.
Is it safe to drive with P2BA6?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelySCR catalyst substrate aged or contaminated
- PossibleThermal damage from prior over-temperature event
Symptoms
- Check engine light on
- Failed emissions inspection
- Possibly slightly increased fuel consumption
- Sulfur (rotten egg) smell from exhaust under load
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–8 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Scr Catalyst, Reductant Dosing Unit
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.