P22FB — NOx Sensor Performance - Sensing Element (Bank 1 Sensor 1)
The wide-band sensing element of the NOx sensor on bank 1 sensor 1 reports an internal performance fault — typically poisoning, condensate damage, or end of service life.
General code reference. Confirm the definition and diagnostic procedure for your vehicle's year, model and engine. A stored code alone does not identify a failed part.
Affected components
- Nox sensor
Possible causes to check
These are possible checks, not a ranked diagnosis. Follow the vehicle manufacturer's test procedure before replacing parts.
- Element poisoned or end of life
- Sensor element aged beyond calibration window
- Sensor element contaminated by oil, soot or coolant
Possible 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)
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
Sources
Check each reference's vehicle and model-year scope. General background links do not establish which fault is most likely on your vehicle.
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.