OBD-II code · Powertrain (generic, extended)
P23BF NOx Sensor Performance Slow Response Low to High Bank 1 Sensor 3
NOx Sensor Performance Slow Response Low to High Bank 1 Sensor 3: the component is electrically intact but its response does not match the command.
Is it safe to drive with P23BF?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySensor element aged
- Less likelySensor element contaminated by oil, soot or coolant
- Less likely5V/reference voltage unstable under load
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
Related codes
- P23BCNOx Sensor Calibration Memory Bank 1 Sensor 3
- P23BDNOx Sensor Performance Signal Biased or Stuck High Bank 1 Sensor 3
- P23BENOx Sensor Performance Signal Biased or Stuck Low Bank 1 Sensor 3
- P23C0NOx Sensor Performance Slow Response High to Low Bank 1 Sensor 3
- P23C1NOx Sensor Sensing Element Bank 1 Sensor 3
- P23C2NOx Sensor Delayed Response High to Low Bank 1 Sensor 3
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.