Powertrain
generic / SAE
P221D
Reductant Heater B Current Too High
DEF heater B current draw exceeds threshold — element partially shorted.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number2 / 1D
Possible causes
- Element partially shorted 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 b
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012