A Japanese manufacturer of ignition coils that were sold to Ford Motor Co., Toyota Motor Corp. and Subaru parent Fuji Heavy Industries Ltd. has agreed to plead guilty and pay a $19 million fine for its role in a conspiracy to fix prices of automotive components, the U.S. Department of Justice said.

The plea agreement with Diamond Electric Manufacturing of Osaka, Japan, marks the first time that the Justice Department’s broadening automotive parts price-fixing probe has involved parts sold to an automaker headquartered in the United States.

The department also revealed that a Japanese executive for Swedish auto supplier Autoliv Inc. has agreed to plead guilty to conspiracy for fixing prices on seat belts sold to Toyota.

Takayoshi Matsunaga, an employee of Autoliv and former vice president of the Toyota global business unit at Autoliv Japan, agreed to serve one year and one day in a U.S. prison, and to pay a $20,000 criminal fine.

As part of their plea agreements, Diamond Electric and Matsunaga have agreed to cooperate in the investigation, the department said.

Ten automotive suppliers and 15 executives have agreed to plead guilty to price-fixing charges during the antitrust probe in the United States, which has been ongoing for more than two years and resulted in $828 million in fines, the department said.

Autoliv agreed in June 2012 to plead guilty to price fixing and pay a $14.5 million fine.

A similar antitrust investigation has been ongoing in Europe, with additional charges involving wire harness suppliers emerging last week.

The department said Diamond Electric conspired with others to rig bids for ignition coils that were ultimately sold to Toyota, Ford and Fuji Heavy Industries or their subsidiaries in the United States from July 2003 to at least February 2010.

In a statement, Diamond said it will continue to cooperate with the investigation.

“Diamond Electric apologizes and accepts complete responsibility for its activities,” the statement said. “To make certain that Diamond Electric respects and complies with the antitrust laws in all jurisdictions around the world, the company has established a comprehensive antitrust compliance program, both in Japan and in the United States.”

The department also said Matsunaga, a Japanese national, conspired to fix prices of seat belts sold to Toyota from May 2008 to at least February 2011 by coordinating bids with other suppliers.