OBD-II code · Powertrain (generic)
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.
Is it safe to drive with P05ED?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySupply voltage 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)
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.6–2 h
- Emissions test
- Likely to fail
- Parts involved
- Reductant Heater Control Module
Related codes
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.