Tesla under US investigation for unexpected braking

Elon Musk accuses accuses investigators of harassing him with investigations and subpoenas

Tesla chief executive Elon Musk has been fighting with federal and California government agencies for years. Reuters

US car safety regulators have launched another investigation of Tesla, this time tied to complaints that its vehicles 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 investigation covers an estimated 416,000 vehicles from the 2021 and 2022 model years.

No crashes or injuries have been reported.

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 Thursday by the National Highway Traffic Safety Administration say the vehicles can unexpectedly brake at motorway speeds.

“Complainants report that the rapid deceleration can occur without warning and often repeatedly during a single drive cycle,” the agency says.

The investigation is another in a string of enforcement efforts by the agency that include Autopilot and “Full Self-Driving” software. Despite their names, neither feature can drive the vehicles without people supervising.

It’s the fourth formal investigation into the car maker in the past three years and NHTSA is supervising 15 Tesla recalls initiated 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 chief executive Elon Musk has been fighting with federal and California government agencies for years, sparring with NHTSA and most notably with the Securities and Exchange Commission.

Early on Thursday, lawyers for Mr Musk sent a letter to a federal judge in Manhattan accusing the commission of harassing him with investigations and subpoenas over his Twitter posts.

The letter from lawyer Alex Spiro accuses the commission of trying to “muzzle” Mr Musk, largely because he's an outspoken government critic.

“The [commission's] outsize efforts seem calculated to chill his exercise of First Amendment rights rather than to enforce generally applicable laws in an even-handed fashion,” the letter states.

Last week, the NHTSA made Tesla recall about 579,000 vehicles in the US because a “Boombox” function can play sounds over an external speaker and obscure audible warnings for pedestrians of an approaching vehicle.

Mr Musk, when asked on Twitter why the company agreed to the recall, responded: “The fun police made us do it [sigh].”

The Washington Post reported a surge in phantom braking complaints from Tesla owners on February 2.

Other recent recalls by Tesla were for “Full Self-Driving” equipped vehicles that were programmed to run stop signs at slow speeds, heating systems that don’t clear windshields quickly enough, seat belt chimes that don’t sound to warn drivers who aren’t buckled up and to fix a feature that allows movies to play on touch screens while cars are being driven.

Those issues were to be fixed with online software updates.