P268F: cylinder 4 injector adjustment code has not been stored

P268F identifies cylinder 4's injector-data programming check. The cited table names DID $63 for its end-of-line injector adjustment, or EIA, record. The stated failure is that this code has not been programmed.

Why the generic title can mislead

“Injector data incompatible” may sound like proof of an incorrect physical injector. This monitor instead asks whether the required adjustment record has been successfully written. It provides no injector part-number comparison, flow test or electrical-resistance limit.

Ignition must be on and the diagnostic enabled by calibration. Controller production/development conditions determine eligibility. The table assigns Type A, one-trip reporting and gives no timing counter. These conditions should not be interpreted as instructions to modify manufacturing-state settings.

Verification after a programming-related concern

Review the cylinder-4 coding result using the correct service process and injector adjustment information. A completed record for another cylinder cannot demonstrate that DID $63 passed its own presence check. Do not invent or duplicate data merely to satisfy the flag.

Confirm that the controller recognizes cylinder 4's EIA code as successfully programmed and that the enabled diagnostic passes. A warning lamp that stays off before the check runs is insufficient evidence. The source establishes this data-state distinction but does not prescribe injector replacement or locate cylinder 4 on a particular engine.

Source and application limits

This explanation covers the cited 2025 GM monitor. Confirm the vehicle and calibration in its service information before applying these limits; inclusion in this file does not establish model compatibility. GM diagnostic parameters, PDF page 1512.