My wife put the gas cap on with out completely tightening it and the check engine light came on. The car was topped off with fuel and the cap tightened properly. The check engine light is still on. It is throwing a p0442 and po455 code. Evap control system leak small and gross. Could that be from the cap not sealing properly? The cap was pressure tested and checked ok. Could it be the car has not been driven enough to reset? This happened once before with the exception it was discovered as soon as the light came on, tightened and then the light went off in about 5 min.

 

Welcome to DF
It could.I would may someone that has a scanner for your car and clear the codes and perform a evap test and see if it pass the test. If it doesn't then you may have a bad hose.