A P0302 code on your 2022 GMC Sierra signals that the engine control module has detected cylinder 2 misfiring beyond acceptable limits. The Sierra's multiple engine options require different diagnostic approaches.
Engine-Specific Diagnosis
The 2022 Sierra lineup includes the 2.7L turbocharged four-cylinder, 5.3L V8, 6.2L V8, and 3.0L Duramax diesel. Identifying your engine is the first step toward accurate diagnosis. The V8 engines feature Dynamic Fuel Management cylinder deactivation.
DFM-Related Misfires
GM's Dynamic Fuel Management system on V8 engines can deactivate cylinder 2 under light load conditions. The hydraulic lifters that enable this feature can develop issues causing misfires. Listen for unusual valve train noise that might indicate lifter problems.
Ignition System Check (Gasoline Engines)
For gasoline-powered Sierras, the ignition system is a primary suspect. The coil-on-plug design means each cylinder has its own coil pack. Test or swap the cylinder 2 coil to verify functionality. Spark plug condition should also be assessed.
Diesel Engine Focus
The 3.0L Duramax inline-six diesel doesn't use spark ignition. P0302 on this engine indicates fuel injection or compression issues. The piezo fuel injectors require specialized testing equipment available at dealers.
Fuel System Evaluation
All Sierra engines benefit from fuel system inspection. Check fuel pressure, injector operation, and fuel quality. Direct injection engines (all 2022 Sierra powertrains) can develop carbon buildup on intake valves affecting performance.