Check the accounts of German car trader first (5)
I believe the answer is:
audit
'check the accounts of' is the definition.
(I've seen this in another clue)
'german car trader first' is the wordplay.
'german car' becomes 'audi' (I've seen this in another clue).
'trader first' becomes 't' (1st letter of 'trader').
'audi'+'t'='AUDIT'
(Other definitions for audit that I've seen before include "vetting of books" , "review of books" , "Conduct annual check of firm's accounts" , "Roman Aquae Sulis" , "Examine account" .)