P23CEFuel Heater Control Module Feedback Signal Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- Unlike the open and short codes, P23CE concerns a feedback signal that is electrically present but does not fit what the engine module expects. The heater unit may, for example, report no temperature rise during a commanded heating phase, a rise that is far too slow, or values that contradict the command state. Bosch's Flexstart heater unit measures the heat it delivers and passes it on, so a weak heating element, poor contact on a high-current path or a drifting measurement can all surface here. No manufacturer documents P23CE or its thresholds publicly. CARB asks for functional checks on heated fuel preparation, not only circuit checks. Cold starts on ethanol may be slow even though no wire is broken; a missing signal is P23CD.
- What you may notice
- Slow or rough cold starts on ethanol without a wiring fault
- Engine warning lamp, depending on manufacturer
- Likely causes
- PossibleAged heating element delivering less heat than commanded
- PossibleHigh resistance at heater power or ground terminals
- PossibleDrifting temperature or current measurement inside the heater unit
- RareWeak battery reducing heating power during cranking
- 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: €80 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.