P0358: Coil H circuit diagnosis needs its internal channel mapping

P0358 is cataloged as ignition coil H primary control circuit/open. The GM summary’s strategy sentence instead names coil F. That naming difference needs calibration-specific mapping before either label is used to select a physical ignition output.

The source supports the electrical principle

The monitor detects low feedback while the primary low-side driver is off. It uses a 0.4-second assessment and two-trip reporting. Ignition synchronization and engine speed above 1,400 rpm are required.

The row also waits for more than nine ignition-counter increments, intended to ensure that every cylinder has fired at least once. This distinguishes the qualified running monitor from an arbitrary measurement of an inactive output.

Confirm identity before localization

Keep the actual P0358 fault detail and the calibration’s output assignment together. The generic H label and the source’s internal F wording do not establish a physical-coil mapping by themselves; confirm that relationship in the correct service information.

The unusually large upper supply boundary in the table is not a practical test instruction. Neither that number nor the open-load label identifies the exact failed connection or component. Once the output is correctly mapped, use the vehicle-specific circuit procedure to distinguish load, wiring and driver possibilities. The source supports an electrical continuity investigation; it does not establish weak spark, a failed plug or automatic coil replacement.

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 703.