P026C: released fuel correction falls below its mode-dependent limit

P026C monitors the fuel adjustment value released by GM's FSA strategy. The comparison is against a lower threshold selected for the active combustion-mode group and multiplied by an ambient-pressure correction factor. It does not directly measure a fixed fuel quantity missing from one named cylinder.

Why there is no universal correction number

The active mode selects one of the supporting threshold tables, and ambient pressure changes the comparison. Preserve both the released correction and its mode/pressure context before interpreting the magnitude. A correction taken from a different mode is not automatically comparable.

This implementation requires enabled correction release and appropriate FSA or DFSA learning. Conditions include system voltage above 11 V, ambient pressure above 70 kPa and an engine-speed range above 1,100 and below 1,800 rpm. The continuation specifies injected quantity above 17 and below 50 mm³, plus stability and vehicle-speed gates.

Verification must reach the learning window

The monitor counts 200 failures out of 400 samples in a 25-millisecond task and uses Type B, two-trip reporting. A parked idle check is unlikely to recreate the documented moving, stable operating conditions and cannot substitute for monitor completion.

Review related learning and input faults before interpreting the correction as an injector diagnosis. Verification should show an acceptable released correction in an eligible mode. The code alone supplies no injector-replacement or high-pressure fuel-testing instruction.

Source and applicability

GM 04B, PDF page 1126; GM 04B, PDF page 1127. This explanation covers the documented 2025 monitor. Confirm the vehicle's module, engine and calibration before applying these criteria; the document's vehicle list does not establish this code's applicability to every listed model.