Code result
P219A
Bank 1 Air-Fuel Ratio Imbalance
Moderate severity
What it means
The fuel-trim values across cylinders on bank 1 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.
Is it safe to drive?
Use caution
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
One injector clogged or leaking
highOne of the most commonly reported causes for this code — check this first.
Vacuum leak at one intake runner
mediumA plausible cause — test and verify before replacing parts.
Low compression on one cylinder
lowLess common, but worth ruling out after the more likely causes.
Related help
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