U05A6Invalid Data Received From Reductant Heater Control Module
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- Diesel exhaust fluid freezes at about -11 °C, and EU rules demanded that it be usable within 20 minutes after a start at -15 °C, so tanks, pumps and lines get electric heaters. Where these heaters are driven by a separate control module, it reports heater states, temperatures and faults to the engine or dosing controller over the bus. U05A6 is stored when those reports arrive but are inconsistent or corrupt. No manufacturer documents this code publicly. CARB 1968.2 requires every component that feeds the emission control or its inducement to be monitored, which covers thaw control. U02A5 means the module is silent, P20B9 points to a heater circuit itself. In cold weather, dosing may start late and warnings may appear.
- What you may notice
- Check engine light or DEF system warning
- Delayed DEF dosing after cold starts
- Likely causes
- PossibleHeater control module electronics faulty
- PossibleWater or salt corrosion at module connector or bus wiring
- RareSoftware levels of heater module and engine controller do not fit
- 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: €100 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.