This is a guess.
I'm thinking that a "breach of car" refers to an break or tear in the car's structure. The breach, or opening in this case, is the broken sunroof.
Usually you hear breach in a physical sense refer to a ship or boat. If the ship has a breach in its hull, it will be letting in water.
A breach in security is an opening in the security of a computer or company, allowing outsiders in.