P049A
EGR B Flow
What it means
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?
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
EGR valve B sticking due to soot
highOne of the most commonly reported causes for this code — check this first.
EGR cooler B partially clogged
mediumA plausible cause — test and verify before replacing parts.
Flow or position sensor drift
lowLess common, but worth ruling out after the more likely causes.
Related help
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