Tesla faces another US investigation: Unexpected braking

U.S. auto safety regulators have launched another investigation of Tesla, this time tied to complaints that its cars can stop on roads for no apparent reason.

The government says it has 354 complaints from owners during the past nine months about "phantom braking" in Tesla Models 3 and Y. The probe covers an estimated 416,000 vehicles from the 2021 and 2022 model years.

The vehicles are equipped with partially automated driver-assist features such as adaptive cruise control and "Autopilot," which allows them to automatically brake and steer within their lanes.

Documents posted on Feb. 17 by the National Highway Traffic Safety Administration say the vehicles can unexpectedly brake at highway speeds.

It's the fourth formal investigation of the Texas automaker in the past three years, and NHTSA is supervising 15 Tesla recalls since January 2021. In addition, the agency has sent investigators to at least 33 crashes involving Teslas using driver-assist systems since 2016 in which 11 people were killed.

Tesla CEO Elon Musk has been fighting with U.S. and California government agencies for years, sparring with NHTSA and most notably with the Securities and Exchange Commission.

Early on Feb. 17, lawyers for Musk sent a letter to a federal judge in Manhattan accusing the SEC of harassing him with investigations and subpoenas over his Twitter posts. In 2018, Musk and Tesla each agreed to pay $20 million in civil fines over Musk's tweets about having the money to take the company private at $420 per share. The funding was far from secured and the company remains public. The settlement specified governance changes, including Musk's ouster as board chairman, as well approval of Musk's tweets.

The letter from attorney Alex Spiro...