WASHINGTON () – A group of 52 auto parts manufacturers has agreed to pay California $23 million as part of a decade-old investigation into antitrust law violations stemming from illegal bid rigging, the state said on Wednesday. Following an investigation by the U.S. Justice Department that began about 10 years ago, 46 companies agreed to pay a total of nearly $3 billion in fines while pleading guilty to price-fixing and bid-rigging in the auto parts industry. More than 22 million cars are registered in California, the most of any U.S. state. The largest California settlement is with Japan’s Denso Corp (6902.T) for $4.25 million, California Attorney General Xavier Becerra said in a statement. Denso said on Wednesday it “has instituted extensive group-wide efforts to ensure we are in total compliance with applicable antitrust laws.” The company added it is “committed to taking any action necessary to ensure Denso remains in complete accordance with applicable antitrust laws.” In 2013, the Justice Department said international price fixing conspiracies affected more than $5 billion in automobile parts used in U.S. vehicles; in total, more than 25 million cars purchased by American consumers were affected. Denso pleaded guilty to price-fixing in 2012 and agreed to pay a $78 million fine to settle a Justice Department probe. A total of 32 auto parts executives also pleaded guilty, including several Denso executives. Law enforcement authorities in the United States and elsewhere have brought price-fixing cases related to seat belts, radiators, windshield wipers, air-conditioning systems, power window motors and power steering components among other parts. A separate settlement has been reached for up to $1.2 billion covering auto purchasers who sued saying the price fixing and bid rigging had caused millions of consumers and businesses from around the country to pay more for some new or leased vehicles and replacement parts. Other California settlements include nearly $1 million for Toyoda Gosei Co (7282.T) signed last month. Reporting by David Shepardson in Washington; Editing by Matthew Lewis and David GregorioOur Standards:The Thomson Trust Principles.