What does code P23B5 mean?

DTC codes / P23xx · Ignition system and misfire / P23B5

P23B5NOx Sensor Heater Sense Circuit Range or Performance Bank 1 Sensor 3

P23B5 means the engine computer has detected that the heater circuit inside the nitrogen oxide (NOx) sensor for Bank 1 Sensor 3 is not performing within its expected range, so the sensor cannot reach operating temperature correctly. The computer monitors the heater's electrical feedback and flags this code when the voltage or current response falls outside the calibrated window during warm-up or steady operation.

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.