The contact owned a 2011 Jaguar XJ. The contact stated that while driving at an undisclosed speed, the vehicle decelerated independently. The contact pulled over to the shoulder of the roadway and had the vehicle towed. The contact stated that several unknown warning lights were illuminated. The vehicle was towed to the dealer, who diagnosed a failure with the engine. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 134,000.