P219B
Bank 2 Air-Fuel Ratio Imbalance
The fuel-trim values across cylinders on bank 2 differ enough that the bank-average air-fuel ratio is biased — a single cylinder is significantly leaner or richer than the rest. Detected by short-term-fuel-trim variance or by the wide-band O2 sensor harmonic monitor.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: hard
Common causes
Ordered by how often each turns out to be the cause.
- One injector clogged or leakingCommon
Parts involved
- Fuel Injector
- Oxygen Sensor
P219B is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.