Nine Japanese auto parts manufacturers and two of their executives will plead guilty and pay $740 million in criminal fines for conspiring to fix the prices of more than 30 products sold to many of the world’s largest automakers operating in the U.S., the Justice Department announced Thursday.

The action is the latest development in the largest criminal investigation the Justice Department’s criminal division has ever carried out. To date, it has resulted in charges against 20 companies and 21 executives, and the companies have agreed to pay $1.6 billion in criminal fines.

From steering assemblies to seat belts, the price-fixing conspiracies went on for more than a decade and affected more than $5 billion in auto parts sold to U.S. car manufacturers and installed in cars sold in the United States and elsewhere. In all, more than 25 million cars purchased by American consumers have been affected by the illegal conduct.

“As a result of these conspiracies, Americans paid more for their cars,” Attorney General Eric Holder told a news conference. Holder said American companies such as Chrysler Group LLC, Ford Motor Co. and General Motors Corp. were affected, as were U.S. subsidiaries of Honda Motor Co., Mazda Motor Corp., Mitsubishi, Nissan Motor Co., Subaru and Toyota Motor Corp.

The government will continue to “check every hood and kick every tire” to end the price fixing, said Holder.

Company executives used code names and met face to face in remote locations in the U.S. and Japan to rig bids, fix prices and allocate the supply of auto parts, the government alleged.

Seventeen of the 21 executives charged so far have been sentenced to serve prison terms in the U.S. or have plea agreements calling for significant time behind bars.

The companies charged Thursday are Hitachi Automotive Systems; Mitsubishi Electric and Mitsubishi Heavy Industries; Mitsuba; Jtekt; NSK; T.RAD; Valeo Japan and Yamashita Rubber.