Powertrain
generic / SAE
P23BD
NOx Sensor Performance Signal Biased or Stuck High Bank 1 Sensor 3
The NOx sensor on bank 1 sensor 3 reports a value that stays at the upper end of its range despite changing engine conditions - sensor element biased or stuck high.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number3 / BD
Possible causes
- Sensor element biased high high
- Sensor element aged beyond calibration window low
- Sensor element contaminated by oil, soot or coolant 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)
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 400–850 €
- Estimated time: 1–2 h
- Component: nox sensor b1s3
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012