Tesla under fire again as US Consumer Reports slams reliability of Model S sedan, causing shares to dive

Consumer Reports said it would no longer recommend Tesla’s Model S sedan due to reliability concerns, in a blow to the luxury electric-powered car initially awarded the highest-ever score in the US magazine’s performance ratings.

The decision, based on the influential publication’s annual survey of vehicle reliability, sent shares of Tesla Motors reeling and underscored the risk of introducing cutting-edge fuel-saving technology and digital multimedia systems in vehicles.

Consumer Reports found "an emerging trend of increased troubles" with a broad range of vehicles that use new transmission technology to boost mileage. The survey was presented by the magazine’s editors at a meeting of Detroit’s Automotive Press Association on Tuesday.

The findings illustrate automakers’ challenges as consumers and regulators demand more innovation. Groundbreaking technology comes with a heightened risk of malfunctions over the life of a vehicle, compromising the reliability car owners enjoy from more mature technology.

Tesla’s stock fell as much as 11.4 per cent before closing down 6.6 per cent to US$213.03 after the magazine said Tesla owners reported "an array of detailed and complicated maladies" in their Model S sedans.

Still, 97 per cent of Tesla owners would buy another Model S, the magazine found, citing quick responsiveness on repairs from the Palo Alto, California-based company "with a minimum of fuss to owners."