P268C code meaning
Cylinder 1 Injector Data Incompatible
Powertrain system Generic code P26xx codes Check engine light
What P268C means
Every modern diesel injector carries a correction code from the factory flow test, and the controller must hold the code of the injector in cylinder 1. P268C sets when that code is missing, outside its range or fails the checksum. GM's 2014 four-cylinder diesel table (14OBDG04) checks the injector quantity adjustment (IQA) checksum once per drive cycle before driving, Type B. Later GM V8, six- and four-cylinder diesel tables rate it Type A, set if the code at DID $60 was never written. Ford's 2023 diesel summary (6.7 L and 3.0 L) runs the check continuously within about 0.5 s. Cylinder 1 exists on every engine, so this is the most widely used code of the series.
P268C at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.3 to 1 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P268C
- Check engine light on
- Uneven running or knock from cylinder 1
Common causes of P268C
- Most likelyCorrection code of a new cylinder 1 injector not entered
- PossibleCode entered with a typing error, so the checksum fails
- PossibleController replaced without transferring injector codes
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Fuel injector cyl1Control module
What each part of P268C means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 6 | Area: computer (engine control module) and output circuits. |
| 8C | The exact fault in that area. |
What to do next
- Note P268C 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 P268C
What does P268C mean?
P268C means "Cylinder 1 Injector Data Incompatible". Every modern diesel injector carries a correction code from the factory flow test, and the controller must hold the code of the injector in cylinder 1. It is a generic code, so it means the same on every make.
Is it safe to drive with P268C?
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 P268C fail an emissions test?
Yes, it can. P268C 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 P268C to fix?
Difficulty: medium. A typical repair takes 0.3 to 1 hours of work. This is a job for a workshop.
Will P268C clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.