P23D5 code meaning
Cylinder 2 Fuel Heater Control Circuit/Open
Powertrain system Generic code P23xx codes Check engine light
What P23D5 means
Cylinder 2 has its own fuel heating path on flex-fuel engines that warm the fuel per cylinder, and P23D5 says this path carries no current although the heater is commanded on, or the control line shows a general fault. To the heater unit the open simply looks like a missing load on channel 2. Bosch describes its Flexstart unit as checking each of four heat circuits for interruption and shorts and passing the result to the engine controller. No carmaker publishes P23D5 or its limits. CARB lists heated fuel preparation among the output systems to be monitored. Cylinder 2 then receives cold ethanol during the first seconds of a cold start. A quick check is to compare the resistance of heater 2 with that of its neighbours. Shorts on the same path are P23D6 and P23D7.
P23D5 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 P23D5
- Cylinder 2 misfires briefly after a cold start on ethanol
- Uneven idle in the first minute when cold
- Engine warning lamp, depending on manufacturer
Common causes of P23D5
- Most likelyHeater at cylinder 2 burnt through (open element)
- PossibleCylinder 2 heater plug loose or not latched after intake work
- PossibleBroken conductor in the cylinder 2 heater lead
- Less likelyChannel 2 output of the heater control unit failed
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 P23D5 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. |
| D5 | The exact fault in that area. |
What to do next
- Note P23D5 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 P23D5
What does P23D5 mean?
P23D5 means "Cylinder 2 Fuel Heater Control Circuit/Open". Cylinder 2 has its own fuel heating path on flex-fuel engines that warm the fuel per cylinder, and P23D5 says this path carries no current although the heater is commanded on, or the control line shows a general fault. It is a generic code, so it means the same on every make.
Is it safe to drive with P23D5?
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 P23D5 fail an emissions test?
Yes, it can. P23D5 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 P23D5 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will P23D5 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.