P23DCCylinder 3 Fuel Heater 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
- P23DC is set when the heating at cylinder 3 works electrically but delivers too little effect. Bosch writes that its heater unit follows the heat output of all four circuits and hands a temperature reading to the engine controller, so a channel that warms more weakly than the others can be singled out. Such systems exist because ethanol-rich fuel is hard to ignite in the cold: Brazilian flex cars long carried a small petrol tank for cold starts, and the 2009 VW Polo E-Flex was the first model to do without it. If cylinder 3 stays underheated, it misfires or runs lean during warm-up. Weak elements, deposits or a high-resistance joint are typical. No manufacturer documents P23DC or its limits; CARB asks for functional monitoring.
- What you may notice
- Misfire on cylinder 3 during warm-up on ethanol
- Lean running in the first minutes
- Engine warning lamp, depending on manufacturer
- Likely causes
- LikelyCylinder 3 heating element below its rated output
- PossibleHigh-resistance crimp or plug in the cylinder 3 heater circuit
- RareDeposits insulating the heated surface
- 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 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.