P2BA8
NOx Exceedence - Interruption of Reagent Dosing Activity
NOx emissions are above the legal threshold and the ECU isolates the cause to interruption of reductant dosing. The injection valve, pump, or supply line is impaired.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: hard
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)
Common causes
Ordered by how often each turns out to be the cause.
- Reductant injection valve cloggedCommon
- Reductant pump output insufficientPossible
Parts involved
- Reductant Injection Valve
- Reductant Pump
- SCR Module
P2BA8 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.