P2BABNOx Exceedence - Incorrect EGR Flow
- 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
- P2BAB attributes excess NOx to exhaust gas recirculation that delivers the wrong amount of gas, so combustion temperature and raw NOx rise. It belongs to the European NOx control rules: Regulation (EU) No 582/2011, Annex XIII, handles tampering-related monitoring through UN Regulation 49 and keeps an EGR valve counter, so an impeded valve leads to warning and inducement. CARB 13 CCR 1968.2 (f)(6.2) separately demands low and high flow detection, normally reported as P0401 and P0402. No maker documents P2BAB publicly; it serves as the emissions link to those EGR flow codes, which point to the actual part. P2BAC is used when EGR is switched off entirely. The driver sees the MIL and, depending on the maker, a NOx warning and later reduced power.
- What you may notice
- MIL on, EGR flow codes stored
- Rough running or sooting with too much EGR
- Power reduction possible if not repaired
- Likely causes
- LikelyEGR valve sooted up or sticking
- PossibleEGR cooler or pipe partly blocked
- PossibleFaulty EGR position sensor or air mass meter distorting flow estimate
- RareLeak in the intake or EGR path
- 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: €150 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.