The newer car players (or the more expensive ones) have better abilities for playing cd-r's & rw's. But for the average car cd player, you need to (1) burn onto a CD-R disk, NOT a CD-RW. (2) Burn at a slow speed (burn at the minimum speed your burner supports). (3) Find cd-r's that can burn at low speeds, not the super fast disks. eg: choose one that burns between speed 1-15 instead of those that burn at up to 45 speed. Car players often don't like the high speed disks. (4) Choose a reliable CD-R brand. NOT those made in China or Taiwan or a nameless/unknown brand. (5) Test the disk on your home stereo player to see if it works. Even then it's no guarantee but will tell you if it works at all outside of the computer.