P2200
NOx Sensor Circuit (Bank 1)
The NOx sensor on bank 1 — typically upstream of the SCR catalyst — does not communicate or sends an invalid signal. NOx sensors are smart sensors with their own controller on the CAN bus; faults often involve heater failure or bus dropout.
- 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.
- NOx sensor failedCommon
- Sensor wiring or CAN harness openPossible
Parts involved
- NOX Sensor
- NOX Sensor Wiring
P2200 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.