Tesla is facing a July 1 deadline to furnish US regulators with information about its biggest-ever recall because drivers using Autopilot keep crashing while using the system.

In a letter posted on its website Tuesday, the National Highway Traffic Safety Administration presses Tesla on how much mileage consumers are racking up using its driver-assistance system, and how many times drivers have been warned to put their hands on the wheel before and after the company’s December recall. The agency announced last month that it was opening up a query into whether Tesla’s over-the-air software update sufficiently prevented misuse after 20 more crashes occurred in the months after the recall.

Tesla didn’t immediately respond to a request for comment. If the company fails to promptly and fully respond to NHTSA, it faces penalties of as much as $27,168 per violation per day, with a maximum fine of more than $135 million, according to the letter.

The information request marks the latest escalation of NHTSA’s examination of Autopilot dating back to August 2021, when the agency opened a defect investigation precipitated by Teslas crashing into first-responder vehicles. In the process of closing that probe and simultaneously opening its recall query, the agency said that Tesla’s means for keeping drivers engaged was weak and its system was too permissive, resulting in a “critical safety gap” between drivers’ expectations and Autopilot’s actual capabilities.

NHTSA has opened more than 50 special crash investigations involving Tesla cars that are suspected to be linked to Autopilot, with the pace of probes picking up under the Biden administration.

Regulators scrutinizing Tesla’s driving systems go beyond NHTSA. The company disclosed in January 2023 that it had received requests for documents from the Justice Department related to Autopilot. Bloomberg also reported that month that the Securities and Exchange Commission was investigating Chief Executive Officer Elon Musk’s role in shaping Tesla’s self-driving claims.