Reductant Quality Sensor Circuit
A general electrical fault is reported on the DEF (urea) quality sensor — measures urea concentration via ultrasonic or refractive method to detect water dilution or wrong fluid.
Affected components
- Reductant quality sensor
- Reductant tank
Common causes
- High likelihood: Sensor failed
- Medium likelihood: Harness fault
Possible 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)
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.