car manufacturer vs auto maker

car manufacturer and auto maker both are nouns.

Word	Noun	Adjective	Verb	Adverb
car manufacturer	Yes	No	No	No
auto maker	Yes	No	No	No

As nouns, car manufacturer and auto maker are synonyms defined as:

car manufacturer and auto maker: a business engaged in the manufacture of automobiles

Other synonyms of car manufacturer include auto manufacturer, automaker, car maker, carmaker.

car manufacturer (noun)	auto maker (noun)
a business engaged in the manufacture of automobiles	a business engaged in the manufacture of automobiles