P02F4: Cylinder 7 injector performance can concern an internal ADC buffer

P02F4 is cataloged as cylinder 7 injector circuit range or performance. The GM table describes a more specific internal check: plausibility of the analog-to-digital converter buffer used during controlled valve operation signal evaluation.

Two positions in the evaluation window

The monitor checks a buffer value at the beginning of the signal-evaluation window and another at its end. Either listed boundary can satisfy the failure logic. These are internal digital counts, not direct injector resistance, fuel quantity or external terminal-voltage specifications.

The row requires ignition on, refers to the common enable and inhibit tables, and specifies 20 events with two-trip reporting. Twenty qualifying events should not be casually translated into twenty seconds or twenty engine starts.

Identify the monitor before selecting a test

Preserve the manufacturer-specific fault description and the diagnostic operating context. A general cylinder-balance result or a fuel-rail pressure graph does not directly test whether the internal evaluation buffer met its boundaries.

The source row itself does not provide a physical injector connector map. The cylinder 7 label comes from the canonical code description and must be reconciled with the installed engine’s service information before locating hardware. This monitor does not prove a leaking injector or authorize replacing the controller. The applicable circuit and signal-evaluation procedure is needed to determine why the buffer values became implausible.

Source and applicability

This explanation covers the cited GM monitor, not every vehicle carrying this code. The application-matrix filename does not resolve cleanly to this file, so no model or engine fitment is assigned. GM diagnostic table, PDF page 609.