P2211
NOx Sensor Heater Sense Circuit Intermittent (Bank 2)
The heater sense line on the bank 2 NOx sensor produces intermittent readings. Often a thermal fault inside the sensor or a connector under temperature cycling.
- 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.
- Connector intermittent under temperatureCommon
- Sensor heater intermittent when hotPossible
- Harness routed against vibrating componentLess likely
Parts involved
- NOX Sensor B2
- NOX Sensor Heater
P2211 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.