For Subaru, any time the car has any issue, the check engine, traction control, and flashing cruise control light will be on at the same time. The car auto disables those functions when check engine light is on. From your description, it's the same issue that haven't been fix. They reset the error code after they performed the repair. the check engine light will pop up after X miles if the issue still there. Sometime it takes few try to get it all problem straighten out. I had similar experience with mine, took me 3 trips to the dealership to have everything straighten out. It was a camshaft sensor issue P0019, but turned out they had to reprogram the car and replaced the car's computer part. My dealership was nice enough to offer me a free oil change after all the trouble. But I don't think the Lemon Law apply to your situation. They just simply haven't fix that problem. You can check the paper work they gave you to see the detail of the work they performed on your car. That will give you a better idea of what's wrong and weather it's the same issue or something new.