P2304: Cylinder 2 ignition output remains high in the monitored on state

P2304 reports a short-to-power signature in the cylinder 2 ignition-control output circuit in the reviewed GM source. The generic code calls this ignition coil B primary control high. The OEM row supplies the circuit identity for this implementation, not a universal coil-location map.

How the controller reaches the decision

An output-driver voltage outside its accepted range during the driver-on state indicates the fault. The documented controller specification is less than 100 ohms between the signal and controller power. That characterizes the detection design rather than prescribing a manual live-circuit resistance test.

Command context is essential: a high voltage observed when the system intentionally permits that level cannot be treated automatically as the monitored failure. A useful diagnosis relates the signal to the output's intended state.

Confirm the running conditions

The test requires the engine running and ignition voltage above 11 V. It counts 50 failing observations out of 63, sampled every 100 milliseconds. A static key-on check or a brief voltage excursion does not by itself establish the same result.

If P2304 accompanies combustion-related codes, retain the distinction between the electrical control fault and the resulting cylinder behavior. This table does not measure spark energy or isolate a defective coil from wiring and driver problems.

Following an evidence-based repair, verify correct cylinder 2 output response and completion of the enabled diagnostic. The documented Type A, one-trip response does not provide a mandatory replacement part.

Source and applicability

The documented control architecture and calibration require confirmation for the vehicle being diagnosed. GM diagnostic table, PDF page 643.