If you have insurance can you be sued from your sisters insurance company because you got in an accident with her car?

I am not an attorney, but I am a business owner who has been sued before. You can most definitely be sued. The question as to if they have a case against you or not doesn't matter too much, assuming the loss is only the ammount of the car. Your legal fees in fighting the most baseless claim against you will probably equal the ammount of value of an average car. If there are other damages the strength of their claim against you will come into question. You say you have insurance? You need to approach your insurance company with the claim against you if they haven't already been named as defendents. They will be able to give you more answers. Once again, I am not an attorney. Just giving you my guess based on my experience.