Powertrain, generic (extended)

P2691 Cylinder 6 Injector Data Incompatible

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2691 refers to the injector in cylinder 6. For six-cylinder diesels it is the last of the per-cylinder codes: GM's 2025 table 25OBDG04B stops at P2691, while the V8 table 25OBDG04A goes on to P2693. In both 2025 tables the check is always active on production controllers and fails if the end-of-line adjustment value was never written; as a further guard, a separate plausibility test under P060C looks at the size of the computed adjustment values. GM rates P2691 Type A. Ford's 2023 diesel summary lists it for its 3.0 L and 6.7 L engines. Programming the code printed on the cylinder 6 injector normally clears it; a recurring fault after correct entry points to the controller.

Likely causes

Cylinder 6 injector code missing after replacement
Entered value rejected as implausible by the software
Controller memory fault losing stored injector data

Symptoms

  • Check engine light on
  • Possible knock or smoke from the affected cylinder

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–300
Time0.3–1.5 h

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

Parts involved

fuel injector cyl6control module

Related codes

P2690P2692P2696P0206P02F3P060C

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