"Where is the black car?"
Translation:Dov'è la macchina nera?
"Car" means both macchina and automobile - or its abbreviation auto, so DL should accept both of them.
Anyways just remember macchina is more colloquial but also more generic, indicating any machines and so including automobile/auto. In effect it is translated with "machine" too in other contexts.
Further translations of "car" here: