Powertrain
generic / SAE
P20BE
Reductant Heater B Control Circuit Performance
Reductant heater B is electrically OK but does not warm the line in time — partial winding fault or excessive heat loss.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number– / BE
Possible causes
- Partial winding fault 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