Powertrain
generic / SAE
P20B6
Reductant Metering Unit Heater Control Circuit Performance
Metering unit heater is electrically OK but does not warm the block within the expected time — partial winding fault or excessive heat loss.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number– / B6
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: hard
- DIY: shop recommended
- Estimated cost: 200–1500 €
- Estimated time: 1–4 h
- Component: reductant metering unit heater
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012