P23D7 code meaning
Cylinder 2 Fuel Heater Control Circuit Low
Powertrain system Generic code P23xx codes Check engine light
What P23D7 means
For P23D7 the module reads the cylinder 2 heater control line as low, which on these power circuits nearly always means a path to ground: a chafed wire, a heater element shorted to its body, or fuel or water bridging the connector pins. The short draws more than the channel is meant to carry, so the heater unit protects itself; Bosch mentions reverse-voltage and internal overtemperature protection as well as short detection per circuit. In practice the heater on cylinder 2 is switched off and that cylinder starts cold while cylinders 1, 3 and 4 still get warm fuel; a blown heater fuse is possible. No manufacturer documents P23D7 publicly; CARB demands circuit checks on this output. High and open on cylinder 2: P23D6, P23D5; cylinder 1 equivalent: P23D3.
P23D7 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 P23D7
- Rough cold start on one cylinder
- Fuel heater fuse blown
- Engine warning lamp, depending on manufacturer
Common causes of P23D7
- Most likelyCylinder 2 heater wire chafed through to ground
- PossibleHeating element at cylinder 2 shorted to its housing
- PossibleFuel or water bridging pins in the cylinder 2 heater plug
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 P23D7 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. |
| D7 | The exact fault in that area. |
What to do next
- Note P23D7 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 P23D7
What does P23D7 mean?
P23D7 means "Cylinder 2 Fuel Heater Control Circuit Low". For P23D7 the module reads the cylinder 2 heater control line as low, which on these power circuits nearly always means a path to ground: a chafed wire, a heater element shorted to its body, or fuel or water bridging the connector pins. It is a generic code, so it means the same on every make.
Is it safe to drive with P23D7?
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 P23D7 fail an emissions test?
Yes, it can. P23D7 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 P23D7 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will P23D7 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.