NOx Sensor Range/Performance (Bank 1)
The bank 1 NOx sensor reports values outside the plausibility window against modeled NOx and the downstream sensor. Often slow response from contamination by oil ash or coolant.
Affected components
- Nox sensor
Common causes
- High likelihood: NOx sensor aged — slow response
- Medium likelihood: Sensor element contaminated
- Low likelihood: Sensor element aged beyond calibration window
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
- A drive cycle may be required after repair
Related codes
Sources
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.