P220F
NOx Sensor Heater Control Circuit Range/Performance (Bank 1 Sensor 2)
The heater control loop for the NOx sensor at bank 1 sensor 2 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.
- 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 ageingCommon
- Sensor element aged beyond calibration windowLess likely
- Sensor mounting loose - signal dampingLess likely
Parts involved
- NOX Sensor
P220F 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.