P23D6Cylinder 2 Fuel Heater Control Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P23D6 flags the control circuit of the cylinder 2 fuel heater as high. A heater driver typically checks the line both with the channel off and with it on; a level that stays near supply voltage in both states points to a control wire touching a positive feed or to a driver that no longer pulls the circuit down. Depending on the wiring, the heater then either stays energized or cannot be switched at all. Bosch documents that its Flexstart unit also diagnoses the FET switches of every heat circuit individually, and that is where a fault of this kind surfaces. P23D6 itself appears in no public manufacturer document, while CARB counts heated fuel preparation among the outputs to watch. Expect either a cold cylinder 2 at start or a heater that runs on. Low and open faults: P23D7, P23D5.
- What you may notice
- Heater at cylinder 2 runs on or does not switch
- Cylinder 2 starts cold on ethanol
- Engine warning lamp, depending on manufacturer
- Likely causes
- LikelyCylinder 2 heater control wire touching a positive feed
- PossibleSwitching FET of channel 2 failed in the conducting state
- RareBent connector pin touching a supply terminal
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €60 – €500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.