P02A5: Cylinder 3 injector leakage is inferred from combined evidence

P02A5 identifies suspected leakage from cylinder 3’s injector. GM’s example calls the monitored condition a mechanical failure with the high-pressure injection valve open. The controller infers that condition from two pieces of operating evidence, rather than directly measuring fuel escaping the injector.

Misfire alone is not the complete trigger

The row combines a cylinder 3 misfire count above 100 with a minimum-error status from fuel-rail pressure control. A generic misfire complaint without that pressure-control evidence is not the same monitor result.

The eligible engine-speed window is above 1,520 and below 6,000 rpm, with relative air charge below 100 percent. Electrical injector failures must be absent, and statistical inhibition must not be active. The row specifies a five-second assessment and two-trip reporting.

Confirm the cylinder and pressure evidence

Preserve cylinder-specific counters together with rail-control fault status. If only a total misfire number is available, it cannot show that cylinder 3 supplied the evidence used here. Cylinder numbering must come from the installed engine’s service information, not an assumed bank arrangement.

This strategy is shared by neighboring cylinder-leakage codes; P02A5 selects cylinder 3. It narrows the investigation but does not by itself prove a physical leak or select a replacement injector. High-pressure fuel-system confirmation belongs to the appropriate professional service procedure, without loosening lines or performing improvised leak checks.

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 705; GM diagnostic table, PDF page 706.