P23D6 code meaning
Cylinder 2 Fuel Heater Control Circuit High
Powertrain system Generic code P23xx codes Check engine light
What P23D6 means
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.
P23D6 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P23D6
- Heater at cylinder 2 runs on or does not switch
- Cylinder 2 starts cold on ethanol
- Engine warning lamp, depending on manufacturer
Common causes of P23D6
- Most likelyCylinder 2 heater control wire touching a positive feed
- PossibleSwitching FET of channel 2 failed in the conducting state
- Less likelyBent connector pin touching a supply terminal
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Fuel heater cyl 2
What each part of P23D6 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 3 | Area: ignition system or misfire. |
| D6 | The exact fault in that area. |
What to do next
- Note P23D6 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P23D6
What does P23D6 mean?
P23D6 means "Cylinder 2 Fuel Heater Control Circuit High". P23D6 flags the control circuit of the cylinder 2 fuel heater as high. It is a generic code, so it means the same on every make.
Is it safe to drive with P23D6?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P23D6 fail an emissions test?
Yes, it can. P23D6 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P23D6 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will P23D6 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.