P05EDReductant Heater Control Module Supply Voltage
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- Some diesels use a separate control module or power stage for the DEF heaters in tank, pump and lines; without heating, frozen fluid cannot thaw in winter and dosing stays blocked. P05ED reports that this module's supply voltage is outside its allowed window – a blown main fuse, an open feed or ground, or system voltage too low or too high. Chrysler (FCA) lists this code among those that trigger the DEF inducement: a 'Service DEF System' warning, a countdown after 50 miles and no restart after 150 miles (P241D). Thresholds are not published; GM's L5P monitors the comparable heater supply under its own codes and flags a drop of more than 3 V below battery voltage while heating is requested. Start with fuse, feed, ground and battery or charging system.
- What you may notice
- Check engine light on
- DEF/AdBlue warning, possibly countdown to no-restart
- In cold weather: DEF frozen, dosing blocked, further heater codes
- Likely causes
- LikelyMain fuse or feed wire to the heater module faulty, connector corroded (splash zone)
- PossiblePoor module ground
- PossibleWeak battery or charging fault (system voltage too low or too high)
- RareHeater control module faulty internally
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €700
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.