I had the same problem with the same codes. I hate those codes they are so misleading. Stay away from there for a minute and get a gas cap from the dealer. Mine did the same thing and had same codes. All it was is the gas cap. The aveo will only accept a gas cap from the dealer. You cannot use the cheap ones from autozone or advance auto there is something about them that is different. Got the cap from the dealer and cleared the code and gone for good. The code will go away after about 100 miles of driving but try that first befor messing around down there. They dont go that bad that fast usually unless u can visually see a brake in one of the lines or the purge solenoid wires are broke. Just try this and see if it works first. Its emission based only and fixed mine with same codes.