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DTC codes / P23xx · Ignition system and misfire / P23A1

P23A1O2 Sensor Exhaust Sample Error Bank 2 Sensor 2

P23A1 indicates that the powertrain control module (PCM) has detected an error in the exhaust sample being read by the downstream oxygen sensor on bank 2, sensor 2. The sensor's signal is not responding as expected to changes in exhaust oxygen content, suggesting a problem with the sensor itself, its wiring, or an exhaust leak affecting the sample.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaIgnition system and misfire

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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