P2303: Cylinder 2 ignition control is diagnosed electrically low

P2303 is the cylinder 2 ignition-control circuit-low monitor in the reviewed GM table. Its generic coil B label should be matched to the vehicle's circuit documentation before identifying a component; the source does not give a physical cylinder location.

Electrical evidence, not a complete misfire diagnosis

The output driver compares voltage with its permitted range to identify a short-to-ground signature. The document lists a controller design specification of less than 100 ohms between the signal and controller ground. That specification is not an instruction to perform a resistance measurement on an energized ignition circuit.

The engine must be running and ignition voltage must exceed 11 V. The fault decision requires 50 failures out of 63 samples at a 100-millisecond rate, so an isolated low reading outside that context is insufficient to reproduce it.

Command-state wording needs confirmation

The strategy text places the check in the powered-off state, while the malfunction column describes the driver-on state. This unresolved source inconsistency limits any attempt to build a detailed test sequence from the summary alone.

Use the applicable service information to establish the correct command state, then assess the cylinder 2 control circuit and its load. P2303 does not prove a secondary-ignition failure, spark-plug condition or fuel-delivery problem.

Verification should document acceptable electrical behavior under the specified running test and no renewed monitor failure. The source classifies the diagnostic as Type A, one trip, but does not identify which component requires repair.

Source and applicability

The documented control architecture and calibration require confirmation for the vehicle being diagnosed. GM diagnostic table, PDF page 642.