NOx Sensor Heater Control Circuit Range/Performance (Bank 1 Sensor 1)
The heater control loop for the NOx sensor at bank 1 sensor 1 reports off-spec behaviour — heater current draw or response time outside the calibrated range. NOx sensors only operate above ~600 °C, so heater control is critical.
Affected components
- Nox sensor
Common causes
- High likelihood: Heater element ageing
- Low likelihood: Sensor element aged beyond calibration window
- Low likelihood: Sensor mounting loose - signal damping
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
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.