P0352: Cylinder 2 ignition output judged open by its driver

The cited GM P0352 monitor diagnoses an open circuit in cylinder 2's ignition-control output. The generic “coil B” label is broader than the documented implementation, so the actual coil/cylinder mapping should come from the vehicle's service information.

Off-state feedback is the key evidence

The controller checks the low-side output while it is off and compares its voltage with internal limits. Those limits correspond to an open-circuit specification above 30 kΩ relative to controller ground. This does not supply a generic secondary-coil resistance test or establish where the opening occurs.

The running engine and ignition voltage above 11 volts are prerequisites. Fifty failures out of 63 samples, evaluated every 100 milliseconds, produce the stated Type A result. An event may therefore be captured and later disappear before a technician observes live data.

A focused confirmation

Record whether P0352 occurs alone or with other supply/control faults, and retain its original operating conditions. An ignition misfire can be associated with the circuit issue, but the table does not use combustion contribution as its pass/fail measurement.

Use the correct driver circuit procedure to locate the electrical discontinuity. Verification should demonstrate normal off-state feedback through a completed eligible monitor, not only successful starting or a cleared warning. The source gives no automatic instruction to replace coil B, the spark plug or the engine controller.

Source and applicability

This explanation is limited to the 2025 GM 25OBDG03A monitor on page 272. Its thresholds are calibration examples, not universal specifications. Confirm the vehicle, engine and controller procedure before applying them.