Tesla Motors says a software update to its Autopilot system will disable automatic steering if drivers don't keep their hands on the wheel. The update also adds multiple features, including improved radar, better voice commands and an industry-first temperature control system that helps prevent kids and pets from overheating. Tesla started moving the update to Model X SUV and Model S sedan owners Wednesday night over the internet. Tesla's Autopilot system, which was unveiled last fall, uses cameras and radar to maintain a set speed, brake automatically and change lanes without the driver's input. Drivers can keep their hands off the wheel for minutes at a time, depending on road conditions.