Reductant Heater Driver Performance
The reductant (AdBlue) tank or line heater driver does not switch as expected. AdBlue may freeze in cold weather, blocking SCR dosing.
Affected components
- Reductant heater
- Reductant control module
Common causes
- High likelihood: Aged driver shows degraded switching behaviour
- Medium likelihood: Heater element resistance drifted out of range
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.