Powertrain
generic / SAE
P21CE
Reductant Quality Module Performance
DEF quality module reports an internal performance fault — self-test failed or measurement loop unable to converge. The module may need replacement.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number1 / CE
Possible causes
- Internal module fault high
- Module software outdated, reflash may resolve low
- Supply voltage outside specification low
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 quality sensor
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012