OBD-II code · Powertrain (generic, extended)

P23B6 NOx Sensor Supply Voltage Circuit Bank 1 Sensor 3

The supply voltage to the bank 1 sensor 3 NOx sensor is outside the calibrated window.

Is it safe to drive with P23B6?

Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.

Common causes

  • Most likelySupply voltage low

Symptoms

  • Check engine light or NOx warning on
  • AdBlue/DEF level or quality warning
  • Possible no-start countdown after ignore period
  • Failed emissions inspection (NOx)

Repair at a glance

Difficulty
Medium
DIY friendly
Best left to a mechanic
Typical labour
1–2 h
Emissions test
Likely to fail
Parts involved
Nox Sensor B1s3

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.