Powertrain
generic / SAE
P21CA
Reductant Control Module Supply Voltage Circuit
Internal monitoring of the SCR control module reports a fault on its main supply voltage rail — separate from the relay-control diagnostics, this is the module's own self-diagnosis of its supply pin.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number1 / CA
Possible causes
- Module supply pin 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: 200–2500 €
- Estimated time: 1–4 h
- Component: scr control module
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012