DTC codes / P22xx · Fuel and air metering (injector circuits) / P22A1
P22A1 means the powertrain control module has detected an abnormally high voltage on the signal circuit of the downstream nitrogen oxide sensor on bank 1, which is the sensor after the catalytic converter on that cylinder bank. The computer expects the sensor's output to stay within a calibrated low-voltage range, and a sustained high reading tells it the circuit is shorted to voltage or the sensor's internal electronics have failed.
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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