P2691: cylinder 6 injector adjustment record has not been programmed

P2691 concerns the cylinder 6 end-of-line injector adjustment record. The documented data identifier is $65. The controller reports failure when that EIA code has not been programmed and success when programming completes successfully.

A record-presence diagnosis

The check requires ignition on, diagnostic calibration enablement and the stated production/development controller qualifications. It is Type A, one trip, with no numeric debounce or sample count supplied. A specific delay should therefore not be inferred from neighboring monitors.

The generic word “incompatible” does not establish that a wrong injector part is installed. This source's decision is about the adjustment record, not a direct fuel-flow or cylinder-balance measurement. That distinction changes the first diagnostic question from “Which part should be replaced?” to whether the correct record exists and was accepted.

Confirming the outcome

Use the vehicle's approved coding procedure and verified injector-specific data for cylinder 6. The table does not provide cylinder location, data format or a raw programming recipe. After any authorized programming, check the controller's completion result and the corresponding diagnostic outcome. Clearing P2691 without establishing successful EIA storage leaves the original criterion unresolved. A passing data check also does not independently certify the injector's mechanical condition; other complaints require their own evidence.

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 1514.