The U.S. federal grand jury has sent a subpoena to Toyota in hopes of getting documents related to unintended acceleration and the braking system of its recalled vehicles. The Los Angeles office of the U.S. Securities and Exchange Commission (SEC) has also sent a subpoena and document request to Toyota as well as its U.S. sales affiliate. The SEC is seeking documents related to unintended acceleration and Toyota's disclosure policies and practices.

A spokeswoman for the U.S. Attorney's Office in the Southern District of New York declined to comment, saying it does not confirm or deny its investigations as a matter of policy. But a subpoena usually means a criminal investigation is under way. The government could be looking into product safety law violations or whether Toyota made false statements to the National Highway Traffic Safety Administration (NHTSA), involving unintended acceleration or the Prius braking system.

The president of Toyota, grandson of Toyota’s founder, Kiichiro Toyoda, plans to testify Wednesday at a session held by the House Committee on Oversight and Government Reform. Originally Toyoda had planned to send executives from Toyota's American operations to the hearings, but after receiving a letter from Edolphus Towns Jr., a Democrat of New York, and chairman of the committee, he decided to attend.

Toyota last week said it was considering a Corolla recall, which would affect more than 500,000 vehicles in the United States. Most of them already are included in the floor mat and pedal recalls.The Corolla was the world’s top-selling car last year and the most popular choice of American drivers who traded in gas guzzlers under the government’s cash-for-clunkers program.