Powertrain
generic / SAE
P049A
EGR B Flow
The exhaust-gas recirculation system has a second EGR loop (B) - typically used on engines with a dedicated low-pressure EGR for emissions or on twin-bank V engines. The ECU detects an EGR B flow fault - the measured or modelled flow does not match the requested rate, without yet diagnosing it as too low or too high.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number4 / 9A
Possible causes
- EGR valve B sticking due to soot high
- EGR cooler B partially clogged medium
- Flow or position sensor drift low
Symptoms
- Check engine light on
- Pinging or knocking under load
- Power loss and hesitation
- Possible rough idle
- Failed emissions inspection (NOx)
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 300–1500 €
- Estimated time: 1.5–5 h
- Component: egr valve b
- Component: egr cooler b
- Component: egr position sensor b
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012