Tesla said the autopilot had been activated last week in California on a deadly dive of the Model X.
For about six seconds, the driver's hands were not on the steering wheel before the Model X collided with a highway median on Highway 101 in Mountain View the company said in a statement released late Friday. And the driver had received "several visual and one audible" cue from the vehicle to grab the wheel "earlier in the ride," it added.
The autopilot function is not completely autonomous. It covers some driving features, but not all, and drivers are expected to stay activated when the feature is enabled.
In a blog post, Tesla called the crash that killed the driver "devastating." It has also been said that drivers are safer if they have autopilot enabled than when they are not activated.
"Tesla autopilot does not prevent all accidents ̵
Related: Tesla Share Drops After NTSB Announces Deadly Crash Investigation
The company also noted a January 2017 government report in which autopilot reduced Tesla's crash rate by 40%.
"The consequences of the fact that the public does not use the autopilot because it is not certain that it is less safe would be extremely serious," Tesla said.
The incident is being investigated by the National Transportation Safety Board and the news came amidst a brutal week of headlines for Tesla as the company continues to struggle with production problems of its new mass-market model 3 car  And a recall for 123,000 model S luxury limousines was issued Thursday on a problem that makes the cars difficult to steer at low speeds.
The company's shares fell more than 22% this month.
The Tesla crash followed a spectacular crash in Tempe, Arizona, where a completely autonomous Uber car killed and killed a pedestrian.
Tesla's semi-autonomous autopilot technology used to be a factor in crashes. In January, a model S limousine hit a fire engine as it drove down a California freeway. The driver was unhurt. And federal investigators found that Tesla's autopilot was partly responsible for the fatal crash of a Model S in 2016.
Tesla vehicles typically rank very high in crash safety. Last June, the Model X was considered the safest SUV ever tested by federal agencies.
CNNMoney (New York) First published March 31, 2018: 1:13 pm ET