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DTC codes / P21xx · Fuel and air metering / P21A2

P21A2Cylinder 7 Air-Fuel Ratio Imbalance

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.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyProfessional
AreaFuel and air metering

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

Running on fumes Free guides aren't free to make. Top up the tank. Any amount, one time. Fuel the Garage