P05ED
Reductant Heater Control Module Supply Voltage
The reductant (AdBlue) heater control module - which warms tank, lines and injector to keep AdBlue from freezing - reports its supply voltage outside the calibrated window.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
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.
- Supply voltage lowCommon
Parts involved
- Reductant Heater Control Module
P05ED 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.