Reductant Level Sensor A Circuit Range/Performance
DEF level sensor A reading is in electrical range but plausibility check fails — value sticks, jumps, or does not match consumption.
Affected components
- Reductant level sensor
Common causes
- High likelihood: Float arm sticks
- Low likelihood: Sensor element aged beyond calibration window
- Low likelihood: Sensor mounting loose - signal damping
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
Related codes
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.