Powertrain
generic / SAE
P056D
Reductant Control Module System Voltage
The reductant (AdBlue) control module reports its supply voltage outside the calibrated window. Reductant dosing is suspended until voltage returns to range, which can drive NOx emissions out of compliance.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number5 / 6D
Possible causes
- Supply voltage low 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: possible
- Estimated cost: 120–500 €
- Estimated time: 0.6–2 h
- Component: reductant control module
- Component: reductant supply relay
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012