P223AReductant Heater E Control Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P223A covers the control circuit of a fifth DEF heating element, heater E. Unlike heaters A to D, which each have four codes for open, performance, low and high, heater E gets only this one code, so any electrical fault of its driver or wiring ends up here. No maker documents P223A publicly. As a reference, GM's 2025 Duramax tables check comparable heater outputs by watching the low-side driver voltage and load current: a fault seen while heating forces the output off so the exact failure can be pinpointed, and heater circuits there are Type A. Which element carries the letter E depends on the system; most published SCR designs stop at three or four heaters. In frost an unheated section may stay frozen, so dosing and SCR monitoring suffer.
- What you may notice
- Check engine light and SCR warning
- DEF dosing delayed or blocked in freezing weather
- Likely causes
- LikelyOpen or shorted wiring or connector of heater E
- PossibleHeating element E burnt out or shorted
- RareFaulty output stage in the controlling module
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.