DTC codes / P23xx · Ignition system and misfire / P23A6
P23A6 indicates that the powertrain control module (PCM) has detected the exhaust heat exchanger bypass valve B is stuck open, meaning the valve is not closing when commanded. The PCM compares commanded valve position with feedback from the valve position sensor and sets this code when the actual position remains open beyond a calibrated threshold.
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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