P223BReductant Heater F 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
- P223B reports a fault in the control circuit of heater F, the sixth heating element of an SCR system. Like its neighbour P223A for heater E, it is a single catch-all code covering open lines and shorts alike. No maker documents P223B publicly, and the published systems show why: Ford's 2023 diesel summary names heaters A to C only (with A and B checked at peak heating power for under 3 A at more than 5 V), and GM bulletin 21-NA-149 lists the heater D codes P20C5 and P20C8 for the 3.0 L LM2 Duramax. Six zones would only appear on layouts with many separately heated lines or tanks. CARB requires every emission-relevant output to be checked for circuit faults. Expect an SCR warning and, in winter, the risk of a frozen line that ends in reduced power.
- What you may notice
- Check engine light and SCR warning
- Reduced power warning after a cold-weather DEF fault
- Likely causes
- LikelyDamaged wiring or corroded connector of heater F
- PossibleHeating element F open or shorted
- RareMissing supply from the heater relay or fuse
- 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.