P02B9: Cylinder 8 leakage evidence must remain cylinder-specific

P02B9 is the cylinder 8 injector-leakage code. In the GM example, the shared fuel rail supplies one part of the evidence, but the combustion counter must belong specifically to cylinder 8. This distinction is useful when a scan tool offers both total and individual-cylinder misfire data.

A shared pressure condition and a local counter

The row requires more than 100 cylinder 8 misfires together with a rail-pressure-control minimum error. It describes the suspected condition as a mechanically open high-pressure injection valve. That conclusion is inferred; no direct fuel-flow measurement is specified in this summary.

Injector electrical faults and statistical inhibition must be absent. The permitted speed window is above 1,520 and below 6,000 rpm, relative air charge must remain below 100 percent, and the evaluation uses a five-second interval with two-trip reporting.

Keep comparisons within the documented scope

Retain cylinder 8’s event history and the simultaneous rail-control state. A rail fault affecting the whole system cannot, by itself, identify which injector the monitor suspected. Similarly, a misfire total that combines several cylinders loses the localization this code relies on.

The table shares its diagnostic pattern with other cylinder leakage codes and does not provide physical cylinder numbering. Verify the engine-specific layout before any service work. Confirmation of a high-pressure injector fault requires the approved fuel-system procedure; this explanation supplies no improvised leak test or automatic replacement instruction.

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 710.