P0264: Cylinder 2 injector circuit low versus normal switching

The documented P0264 monitor concerns a short-to-ground condition on the cylinder 2 injector's low-side circuit. Its evidence comes from the controller's voltage feedback when the output is off. This distinction prevents normal low-side switching from being mistaken for a defect.

Read feedback in its proper state

The source lists a controller specification at or below one volt between the signal and controller ground. The relevant comparison applies during the defined off-state check, not across every point in an injection event. The table gives no universal oscilloscope waveform or connector pin assignment.

The controller must have at least 11 volts of battery supply, and P062B injector-control fault status must permit operation. It samples every 100 milliseconds and uses ten failures in twenty samples for the Type A result.

Narrow the electrical investigation

Confirm which physical injector is cylinder 2 on the actual engine. Compare the code's timing with supply and driver status, particularly if other injector codes occurred at the same time. The appropriate inference is that cylinder 2 feedback was too low for the monitored state; it does not establish an injector-flow problem.

Use the vehicle's direct-injection electrical procedure to localize the ground path. After corrective work, verify the off-state diagnostic completes without repeating the low-feedback fault. Merely erasing the code or observing combustion at idle leaves the actual circuit criterion untested.

Source and applicability

This explanation is limited to the 2025 GM 25OBDG03A monitor on page 228. Its thresholds are calibration examples, not universal specifications. Confirm the vehicle, engine and controller procedure before applying them.