P2205
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.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
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)
Common causes
Ordered by how often each turns out to be the cause.
- Heater element openCommon
- Heater short to supply or groundPossible
Parts involved
- NOX Sensor
- NOX Sensor Heater
P2205 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.