Reductant Quality Module Supply Voltage Low
Supply voltage at the dedicated DEF quality sensor module is below the lower threshold.
Affected components
- Reductant quality sensor
Common causes
- High likelihood: Voltage drop in supply harness
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.