Consumer advocate groups on Monday called upon Attorney General Maura Healey to investigate used car dealer CarMax, claiming that the dealer has sold recalled vehicles to drivers in Massachusetts. The MASSPIRG Education Fund and the Consumers for Auto Reliability and Safety Foundation on Monday reported a joint investigation found that 17 percent of the cars available for purchase at CarMax's North Attleborough dealership were subject to at least one federal safety recall that had not been addressed.