OBD-II code · Powertrain (generic)
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.
Is it safe to drive with P049A?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyEGR valve B sticking due to soot
- PossibleEGR cooler B partially clogged
- Less likelyFlow or position sensor drift
Symptoms
- Check engine light on
- Pinging or knocking under load
- Power loss and hesitation
- Possible rough idle
- Failed emissions inspection (NOx)
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1.5–5 h
- Emissions test
- Likely to fail
- Parts involved
- Egr Valve B, Egr Cooler B, Egr Position Sensor B
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.