P049AEGR B Flow
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- Exhaust gas recirculation (EGR) routes part of the exhaust back into the intake to lower combustion temperature and NOx. Circuit B is the second EGR path; on diesels with two circuits it is the low-pressure EGR, which takes exhaust after the particulate filter and feeds it in before the turbo compressor (GM diesels 2016–18, FCA's 2.2 and 3.0 diesels). P049A is the general flow fault of circuit B, used where the module does not separate too little from too much; CARB requires low and high flow to be detected, mostly by comparing air mass, manifold pressure or lambda with a model. No manufacturer document available to us uses P049A – GM has only position and actuator codes for its low-pressure EGR, FCA uses P049B. Low-pressure EGR is then switched off.
- What you may notice
- Check engine light on
- EGR switched off, usually no noticeable change
- Higher NOx
- Likely causes
- LikelyLow-pressure EGR valve sooted or sticking
- PossibleLow-pressure EGR cooler or line blocked or leaking
- PossibleFlap creating the pressure difference faulty
- PossibleSensors (air mass, pressure difference, position sensor B) implausible
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · 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.