Car Will Not Start problems of the 2009 Volkswagen CC

Tl the contact owns a 2009 Volkswagen Cc. On several occasions, after the vehicle was parked overnight, the battery became drained and the vehicle failed to start. The battery was replaced; however, the failure recurred. The vehicle was not diagnosed or repaired. An independent mechanic was consulted, but was unable to provide a cause for the failure. The vehicle was included in NHTSA campaign number: 17v509000 (fuel system, gasoline). The vehicle was not repaired. An unknown dealer and the manufacturer were notified. The failure mileage was not available.