Powertrain, generic (extended)

P223A Reductant Heater E Control Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

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.

Likely causes

Open or shorted wiring or connector of heater E
Heating element E burnt out or shorted
Faulty output stage in the controlling module

Symptoms

  • Check engine light and SCR warning
  • DEF dosing delayed or blocked in freezing weather

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–1,200
Time1–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

reductant line heater e

Related codes

P223BP20C5P20B9P21C2

References: law.cornell.edu, gsi.ext.gm.com, fordservicecontent.com.