* On a map or GPS: It might indicate a taxi, a rental car location, or a place of interest related to cars.
* On a dashboard: This would be specific to the car's manufacturer and model. It could indicate anything from a check engine light (though that's usually a different color), to a problem with the parking brake, to a malfunctioning lane keeping assist system.
* In a software program: It might represent a user's profile or a car-related feature.
* In a game: Its meaning is totally dependent on the game's mechanics.
Please provide more context about where you saw the yellow car symbol.