DETROIT — Tesla Motors is planning improvements to its semi-autonomous Autopilot system after a fatal crash earlier this summer.

Tesla CEO Elon Musk wrote in a Tweet Wednesday that a software update will be released in a few weeks. He said details would come later Wednesday.

Musk says a software update will make “major improvements” to Autopilot, including more advanced processing of radar signals. Software updates are delivered over the air to Tesla owners.

Tesla’s Autopilot system can maintain a set speed, keep the car within its lane and brake automatically. Radar helps the car see things that may be blocked to cameras in bright sunlight or bad weather.

In May, a driver whose Tesla Model S was operating in Autopilot died after he crashed into a tractor-trailer.