Code result
P21A4
Cylinder 9 Air-Fuel Ratio Imbalance
Moderate severity
What it means
Cylinder 9 fuel trim deviates significantly from the bank average — a single-cylinder injector or intake fault.
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
Injector clogged or leaking
highOne of the most commonly reported causes for this code — check this first.
Related help
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