What does code P23AC mean?

Q: What does code P23AC mean?

NOx Sensor Circuit Bank 1 Sensor 3. P23AC indicates that the powertrain control module (PCM) has detected a fault in the circuit for the third nitrogen oxide (NOx) sensor on bank 1, which is the side of the engine containing cylinder number one. The PCM monitors the sensor's signal and heater circuit for expected voltage and current, and when the readings fall outside the programmed range for a calibrated time, it sets this code and illuminates the check engine light. This sensor is part of the selective catalytic reduction (SCR) system and helps the PCM verify that oxides of nitrogen are being reduced properly in the exhaust.

DTC codes / P23xx · Ignition system and misfire / P23AC

P23ACNOx Sensor Circuit Bank 1 Sensor 3

P23AC indicates that the powertrain control module (PCM) has detected a fault in the circuit for the third nitrogen oxide (NOx) sensor on bank 1, which is the side of the engine containing cylinder number one. The PCM monitors the sensor's signal and heater circuit for expected voltage and current, and when the readings fall outside the programmed range for a calibrated time, it sets this code and illuminates the check engine light. This sensor is part of the selective catalytic reduction (SCR) system and helps the PCM verify that oxides of nitrogen are being reduced properly in the exhaust.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

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.