OBD-II code · Powertrain (generic, extended)
P23AC NOx Sensor Circuit Bank 1 Sensor 3
A general circuit fault on the third NOx sensor of bank 1.
Is it safe to drive with P23AC?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyOpen in sensor or wiring
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
- 1–1.8 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.