According to reports, the Apple Car will run on a custom centrally integrated "carOS" that will control all aspects of the vehicle including navigation, sensor data processing, and infotainment. The report also states that Apple will leverage Korean suppliers for the self-driving sensors in the car's domain control unit (DCU).
https://www.notebookcheck.net/Apple-Car-to-do-a-Tesla-by-featuring-a-custom-centrally-integrated-carOS-for-navigation-and-infotainment.614176.0.html