Tesla is facing a class-action lawsuit from a group of US owners over automatic software updates that reportedly decreased driving range or cause battery failures.

Owners of older Tesla Model S and Model X EVs filed a proposed class-action lawsuit on 12 May in California, claiming that Tesla's updates and their effects are in violation of state and federal laws because they can reduce driving range by up to 20 percent and can require some owners to replace batteries at a cost of $15,000 (approx. £12,000).

Filed in the US District Court in San Francisco, the lawsuit argues impacted Tesla vehicles are "protected computers" under the definition outlined in the Computer Fraud and Abuse Act, and that automatic software updates violate consumers' rights under the law.

The lawsuit also claims Tesla's updates and their effects violate the California Unfair Competition Law and the Consumer Legal Remedies Act.

"Tesla owners and lessors are uniquely at the mercy of the maker of their cars, and Tesla imposes software updates without consent whenever their vehicle is connected to Wi-Fi," said Steve Berman, an attorney with Hagens Berman representing Tesla owners and lessors in the lawsuit, according to Reuters.

Gallery: 2023 Tesla Model S

Attorneys for the owners also say automakers generally notify customers when they want to perform a software update but Tesla can perform automatic updates whenever the vehicle is connected to Wi-Fi, without notifying customers.

According to the lawsuit, some Tesla owners have paid third parties $500-$750 to reverse battery-related software updates that cut their vehicles' driving range.

Attorneys say Model S and Model X owners and lessors who experience reduced battery capacity following a software update are denied reimbursement by Tesla. Some of the owners reported that the automaker told them they needed to have a battery replacement, with Tesla asking as much as $15,000 for a new battery.

This is not the first time the EV maker faces a lawsuit over the same issue. In July 2021, the company agreed to pay $1.9 million to settle claims a software update temporarily reduced maximum battery voltage in 1,743 Model S saloons. About $400,000 of the total sum was represented by attorneys' fees and expenses.

Owners of the vehicles received $625 each, which the court equated to "many times the prorated value of the temporarily reduced maximum voltage."