Check engine light / code P446 and now car wont start.

Hello, the P0446 and fuel tank filling issue is probably related -- this indicates a concern with the evaporative emissions system. This relates to the evaporative emissions system vent valve. If the vent valve is stuck, you may not be able to easily fill the tank -- and there can be other evaporative emissions issues associated for emissions controls. As far as the no start, the only reason this concern could affect the starting is if you're out of gas as a result. Other than that - is the engine cranking at all? If there's no cranking, it could be battery and starting system related. If it's cranking with no start, check ignition spark, fuel delivery, air intake, engine compression and timing. www.repairpal.com/repair-shops

Failed vent valve / solenoid has temporarily flooded engine - holding accelerator pedal to floor while cranking engine will clear flood. This will also cause very slow fuel refill.. Have local auto repair facility perform necessary testing - - scan tool can perform vent valve functional test.. Common GM problem. Good luck!