P2691Cylinder 6 Injector Data Incompatible
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- 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.
- What you may notice
- Check engine light on
- Possible knock or smoke from the affected cylinder
- Likely causes
- LikelyCylinder 6 injector code missing after replacement
- PossibleEntered value rejected as implausible by the software
- RareController memory fault losing stored injector data
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.