P217B: Group G low supply is a repeated on-command electrical result

P217B identifies injector group G supply voltage as low. GM's cited implementation watches the high-side output named injector 7. It evaluates voltage feedback while that driver is on and interprets the abnormal response as a connection toward ground.

The driver state distinguishes the fault

An intentionally inactive output is not equivalent to the energized path being assessed. Preserve the actual on command with the fault result instead of treating a low signal at any time as confirmation. This monitor does not measure delivered fuel quantity or the cylinder's combustion contribution.

The table requires battery voltage of at least 11 V and no applicable P062B active or key-cycle failure state. Ten failed samples within twenty, evaluated every 100 milliseconds, mature the condition. The row lists one-trip reporting separately from the sample count.

Map the correct group before isolating hardware

A healthy neighboring injector output cannot verify the group-G path. The document's injector-7 naming also needs the actual controller configuration before it is translated into a physical cylinder or connector on the vehicle.

A useful diagnostic record retains command, supply, channel identity and the wider injector-control fault status. If the latter prevents monitoring, an absent new result is not proof of a pass. The source cannot distinguish an internal driver problem from a connected circuit defect or justify a specific replacement without the appropriate service procedure.

Source and applicability

2025 GM 06B documented monitor only. Vehicle, engine and controller calibration applicability must be established separately; no model fitment is inferred from the file. GM PDF, physical page 444.