P21E6: The cylinder 6 injector B low-circuit check depends on an inactive stage

P21E6 is listed as cylinder 6 injector B circuit low. The GM table's injector-6 row describes a short-to-ground electrical category and evaluates it with the power stage inactive. This differs from judging the current of an injector that is being commanded on.

The internal criterion needs its context

The listed observation is output voltage above 5 V. Because the source does not identify an external test point or explain the complete driver topology, that figure is not a universal meter specification. The code label and internal diagnostic quantity should both be retained rather than forcing one into an assumed conventional circuit model.

The entry spans two pages. Its continuation includes supply and inhibition information, while the row itself lists a three-event maturation count and minimum engine speed of 80 rpm.

What this check distinguishes

The adjacent injector-6 open-load entry uses a different inactive-stage voltage window. A high-circuit entry instead uses current with the stage active. Those differences help preserve the actual failure class when reviewing diagnostic data.

Confirm the real injector B configuration from vehicle information before selecting a circuit. This monitor does not directly test fueling quantity or mechanical injector behavior and cannot isolate wiring, load or the controller output by itself. A meaningful recovery check needs the proper event and eligibility conditions, not merely an observation that the engine runs or the fault has been cleared.

Source and scope

2025 GM 25OBDG07A Part 2 monitor tables only; model, engine and transmission applicability are not established by the unresolved application-matrix filename join. These are documented monitor criteria, not a universal repair procedure. GM PDF, physical page 557 · GM PDF, physical page 558.