P2225
NOx Sensor Heater Sense Circuit Intermittent (Bank 2)
The feedback line that monitors the NOx sensor heater current draw on bank 2 sensor 1 jumps or drops out intermittently — connector or harness issue.
- 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.
- Intermittent connectorCommon
- Connector with intermittent contact under vibrationLess likely
- Harness routed against vibrating componentLess likely
Parts involved
- NOX Sensor
P2225 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.