P2200NOx Sensor Circuit (Bank 1)
What it means
The ECU sees a fault in the NOx sensor circuit (bank 1). NOx sensors have their own control unit and talk to the ECU over CAN.
Symptoms
- Emissions or AdBlue warning light
- Possibly a countdown to a no-restart condition
Common causes
- Failed NOx sensor (common)
- Wiring or connector fault (heat damage)
- Missing supply or CAN fault to the sensor module
- Exhaust leak near the sensor
What to check first
- Check supply, ground and CAN wiring at the sensor module
- Read the NOx sensor values and status bits
- Check for exhaust leaks before replacing the sensor
Generic OBD-II meaning. Manufacturer-specific meanings and checks can differ; always check the service information for the car.