California regulators are alleging a San Francisco robotaxi service owned by General Motors covered up the severity of an accident involving one of its driverless cars, raising the specter they may add a fine to the recent suspension of its California license.

The potential penalty facing GM’s Cruise service could be around $1.5m, based on documents filed late last week by the California public utilities commission.

The notice orders Cruise to appear at a 6 February evidentiary hearing to determine whether the robotaxi service misled regulators about what happened after one of its driverless cars ran into a pedestrian who had already been struck by another vehicle driven by a human on the evening of 2 October in San Francisco.

The February hearing comes just six months after the commission authorized Cruise’s robotaxi service to begin charging passengers for around-the-clock rides throughout San Francisco, despite strident objections from city officials who warned the driverless cars malfunctioned.

Three weeks after Cruise’s 2 October accident, the California department of motor vehicles effectively shut down the robotaxi service by suspending its license to operate in the state.

The suspension was a major blow for Cruise and its corporate parent, GM, which absorbed huge losses during the development of the driverless service that was supposed to generate $1bn in revenue by 2025 as it expanded beyond San Francisco.

After losing nearly $6bn since the end of 2019, Cruise has shifted into reverse as it scrambles to control the fallout from the 2 October accident, which critically injured the pedestrian and led to the recent resignation of Kyle Vogt, the company’s CEO and co-founder.

Without directly addressing the potential fine, Mary Barra, CEO for GM, said on Monday that the October crash had helped the automaker learn more about the need for transparency and a better relationship with regulators.

“We’re very focused on righting the ship here because this is technology that can make the way we move from point A to point B safer,” Barra said.

Barra also pointed to the overhaul of Cruise’s management that included a reorganization of its government-relations and legal teams as signs of progress. “We think we can do things more effectively,” she said.

Cruise issued its own statement pledging to respond “in a timely manner” to the public utility commission’s concerns. The company has already hired an outside law firm to scrutinize its response to the 2 October accident.

The most serious questions about the incident concern Cruise’s handling of a video showing a robotaxi named “Panini” dragging the pedestrian 20ft (6 meters) at a speed of 7mph before coming to the stop.

In a 1 December filing recounting how Cruise handled disclosures about the accident, the commission asserted the company tried to conceal how its robotaxi reacted to the accident for more than two weeks.

The documents allege Cruise’s concealment started with a 3 October phone call to a regulatory analyst who was told the robotaxi had come to an immediate stop upon impact with the pedestrian without mentioning the vehicle actually drove another 20ft with the injured person still pinned down.

Cruise did not provide the video footage until 19 October, according to the regulatory filing. The cover-up spanned 15 days, according to the commission, exposing Cruise and GM to potential fines of $100,000 per day, or $1.5m.