The value of cars produced by a Japanese company are part of United States Gross Domestic Product (GDP) as long as the cars are produced in a factory located within U.S. territory.
The reason why is that GDP includes the final value of all goods and services produed within a country, during a specific period of time (usually a year). If the cars are produce in U.S. territory, they are counted as part of U.S. GDP, even if the company is from Japan or any other country.
