Ibrahim Namo, who lives in Ealing, ran the companies Top Choice, Smart Autos and M6 Autos from premises in Wembley, the Kilburn Times reported, and he advertised the vehicles he had for sale on Auto Trader, both in the magazine and online.
But Willesden magistrates heard that between October 2012 and March 2013, he dishonestly described several cars, providing false information about mileages, specifications and service histories.
Namo pleaded guilty to three offences under the Consumer Protection From Unfair Trading Regulations 2008, said the newspaper. He was ordered to pay a total of £520.
Cllr George Crane, of Brent council, said the authority was working hard to protect consumers from rogue traders such as Namo.