Underling working next to car (6)
I believe the answer is:
minion
'underling' is the definition.
(I've seen this in another clue)
'working next to car' is the wordplay.
'working' becomes 'on' (on can mean working or activated).
'next to' means one lot of letters go next to another.
'car' becomes 'mini' (Mini Cooper).
'on' after 'mini' is 'MINION'.
(Other definitions for minion that I've seen before include "Flunky" , "Lackey or subordinate assistant" , "flunkey" , "An archaic servant or inferior (6)" , "Servile underling" .)