P0353: Cylinder 3 ignition-control circuit opening versus a weak spark

P0353 is an ignition-control circuit code. This GM monitor specifically checks cylinder 3's low-side ignition driver for an open condition, using feedback measured while the output is off. Its subject is the control circuit, not a direct test of the spark delivered across the plug gap.

Supply and state define the test

The engine must be running and ignition voltage must exceed 11 volts. The controller counts 50 failures among 63 samples at 100-millisecond intervals. The published open-circuit driver specification is above 30 kΩ between signal and controller ground, with voltage limits implemented inside the controller.

A measurement taken during an on command or with inadequate supply is not equivalent to the documented off-state diagnosis. Retain command and voltage context when examining an intermittent event.

Identify the monitored path correctly

The broad generic title may call this coil C, while the primary source calls it cylinder 3 ignition control. Neither label establishes physical placement across all engines. Confirm the engine-specific mapping before choosing a connector or interpreting another cylinder's waveform.

The appropriate diagnostic decision is whether the cylinder 3 control path is electrically open and where. The source does not establish a coil, connector, harness or controller failure by itself. After correction, verify the eligible off-state monitor passes. Smooth running alone does not test every aspect of the driver-feedback circuit.

Source and applicability

This explanation is limited to the 2025 GM 25OBDG03A monitor on page 273. Its thresholds are calibration examples, not universal specifications. Confirm the vehicle, engine and controller procedure before applying them.