NOx Sensor Heater Control Circuit (Bank 1)
The heater inside the bank 1 NOx sensor cannot be controlled — open, short, or failed driver. Without proper heater operation the sensor never reaches its operating temperature and reports invalid data.
Affected components
- Nox sensor
- Nox sensor heater
Common causes
- High likelihood: Heater element open
- Medium likelihood: Heater short to supply or ground
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.