P2BA8NOx Exceedence - Interruption of Reagent Dosing Activity
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- With P2BA8 the controller states that NOx went up because reagent dosing stopped although the engine needed it. Regulation (EU) 2017/1151 Annex XVI, point 5.5, treats such an interruption as a case for the driver warning, unless the system paused dosing on purpose in conditions the maker declared to the authority; if dosing is not restored within 50 km, inducement starts. In California, section (f)(2.2.3)(A) of the OBD rule requires reagent delivery to be monitored. No maker documents P2BA8 publicly. The component fault behind the stop, such as pump P208B, pressure P20E8 or injector P2047, usually sets its own code; P2BA8 marks the emission consequence, while P2BA7 covers an empty tank and P2BAA too little consumption.
- What you may notice
- DEF dosing malfunction message with distance countdown
- MIL on, further SCR component codes stored
- Reduced power or no restart if not repaired
- Likely causes
- LikelyDEF injector clogged or stuck by crystals
- LikelyPump failure or pressure not built up
- PossibleFrozen fluid because tank or line heater fails
- RareWiring or SCR control unit fault stopping dosing
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €100 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.