Powertrain, generic (extended)

P268C Cylinder 1 Injector Data Incompatible

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

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.

Likely causes

Correction code of a new cylinder 1 injector not entered
Code entered with a typing error, so the checksum fails
Controller replaced without transferring injector codes

Symptoms

  • Check engine light on
  • Uneven running or knock from cylinder 1

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–250
Time0.3–1 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

fuel injector cyl1control module

Related codes

P268DP2696P268AP0201P02EE

References: law.cornell.edu, gsi.ext.gm.com, gsi.ext.gm.com, fordservicecontent.com.