P263D
Reductant Heater Driver Performance
The reductant (AdBlue) tank or line heater driver does not switch as expected. AdBlue may freeze in cold weather, blocking SCR dosing.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: hard
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)
Common causes
Ordered by how often each turns out to be the cause.
- Aged driver shows degraded switching behaviourCommon
- Heater element resistance drifted out of rangePossible
Parts involved
- Reductant Heater
- Reductant Control Module
P263D is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.