OBD-II code · Powertrain (generic, extended)
P2BAA NOx Sensor Range/Performance (Bank 1, Sensor 1)
The upstream NOx sensor on bank 1 returns values that are not plausible for the current operating point. NOx sensors are slow to warm up, sensitive to soot and water, and are a frequent failure on diesel SCR systems.
Is it safe to drive with P2BAA?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyNOx sensor element failed
- PossibleSensor contaminated with soot or condensate
- Less likelySensor element aged beyond calibration window
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
- Often, with basic tools
- Typical labour
- 0.5–2 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Nox Sensor Upstream, Nox Sensor Wiring
Related codes
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.