Powertrain
generic / SAE
P21DD
Reductant Heater A Current Too Low
DEF heater A current draw is below threshold — partially-open winding.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number1 / DD
Possible causes
- Element partially open high
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)
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 80–800 €
- Estimated time: 0.7–3 h
- Component: reductant line heater a
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012