DTC codes / P21xx · Fuel and air metering / P21A2
P21A2 indicates that the engine computer has detected an air-fuel ratio imbalance on cylinder 7, meaning that cylinder is not burning fuel and air in the same proportion as the rest of the engine. The powertrain control module monitors crankshaft speed fluctuations and oxygen sensor feedback to identify which cylinder is contributing unevenly to the engine's overall combustion.
Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.
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