If you do not pass the college board exam you are not required to send the scores to a college. Some colleges may ask for your test scores regardless because they can see if you have taken the exam. Your score won’t hurt your chances of getting into college. If you do well it will help you but doing bad won’t affect your chances of going to a private college. Colleges are also looking for the fact that you took the opportunity of taking an AP class. It is great to do well on the exam but if you don’t they will still notice that you took a college-level class as a sophomore.