What does code P23B9 mean?

Q: What does code P23B9 mean?

NOx Sensor Heater Sense Circuit High Bank 1 Sensor 3. P23B9 indicates that the powertrain control module (PCM) has detected an abnormally high voltage on the heater sense circuit for the third nitrogen oxide (NOx) sensor on bank 1. This circuit monitors the electrical current flowing through the sensor's internal heater, and a high reading tells the PCM the heater circuit is drawing too much current or the sense line is shorted to voltage.

DTC codes / P23xx · Ignition system and misfire / P23B9

P23B9NOx Sensor Heater Sense Circuit High Bank 1 Sensor 3

P23B9 indicates that the powertrain control module (PCM) has detected an abnormally high voltage on the heater sense circuit for the third nitrogen oxide (NOx) sensor on bank 1. This circuit monitors the electrical current flowing through the sensor's internal heater, and a high reading tells the PCM the heater circuit is drawing too much current or the sense line is shorted to voltage.

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.