In a letter to FTC Chairwoman Linda Khan, Democrats Ron Wyden of Oregon, and Edward Markey of Massachusetts allege that General Motors, Hyundai, Honda and perhaps others are sharing drivers’ data, such as sudden braking and acceleration.

The automakers, the senators said in a statement Friday, used deceptive tactics to manipulate customers into signing up for disclosure of the data to brokers.

After reading a report in The New York Times, Wyden’s office looked into the three automakers and found that they shared data with broker Verisk Analytics. In the letter to Khan, the senators wrote that all three automakers confirmed disclosure of the data. GM also confirmed that it disclosed customer location data to two other companies that the automaker would not name, the letter said.

Verisk used the data to prepare reports on driving-behavior history and sold them to insurance companies, the letter said. Some automakers may have deceived customers by advertising data disclosures as a way to reduce insurance bills, without telling them that some insurers could charge more, the senators wrote.

“If the FTC determines that these companies violated the law, we urge you to hold the companies and their senior executives accountable,” the senators wrote to Khan.

GM wouldn’t say how many cars’ data was sent to brokers or what it was paid, according to the letter. Wyden’s office found that Hyundai shared data from 1.7 million vehicles and was paid just over $1 million, while Honda got just under $26,000 for data from 97,000 vehicles, the senators said.

A message was left Friday after business hours seeking comment from the FTC.

In an email, GM denied that it deceived customers into enrolling in the data-sharing program with Verisk. Data-sharing partnerships with Verisk and LexisNexis were canceled in March, and its data-sharing program called “Smart Driver” ended in June, GM said.

“Data was only shared with an insurer if a customer initiated a quote directly with their chosen carrier and provided a separate consent to that carrier,” the email said.

The company said it does share “de-identified” data with partners to aid city infrastructure and make roads safer.

In a statement, Hyundai said the senators’ letter mischaracterizes its data policies and that it has safeguards to make sure customers agree to sharing driving information with insurers.

Customers, it said, had the option to connect driving scores to their insurers through Verisk for possible benefits such as good-driving discounts.

“It is important to note that Verisk was not authorized by Hyundai or the customer to share the Drive Score data with insurers until the customer affirmatively consented to this on an insurer’s website or app,” Hyundai said.

Honda also said that customers had to opt into the program with Verisk. Some customers with good driving scores were given the chance to agree to discount offers from insurers. “Without that clear second opt-in by the customer, no identifiable consumer information was shared with any insurance company,” Honda said.

Verisk also disagreed with Wyden and Markey and said in a statement that it “acts to ensure data is accessed and used appropriately.” The company said using data responsibly “is the cornerstone of our business.”