European Union antitrust regulators are set to punish Japanese auto parts makers for allegedly fixing prices of starter motors and accelerator modules, two people familiar with the matter said. The companies in the alleged cartel are world No. 2 parts maker Denso, Mitsubishi Electric Corp and a Hitachi Ltd unit, the people said. The European Commission action will mark the first of several automobile-related cases scheduled for 2016 and is the latest in a series of penalties levied by competition watchdogs in the United States, Europe and Asia against a long-time business model in the industry. That model essentially sees parts makers keep prices relatively high for new components they supply to car manufacturers, and then charge even more for the same parts supplied as replacements to dealerships and repair shops. The Commission briefed national competition authorities on the case earlier on Monday, the people told Reuters. It was not clear if there was a whistleblower among the three Japanese companies. Firms which report a cartel to the European Commission are not sanctioned. Hitachi confirmed the company was under investigation by the European Commission, but declined to comment further. Both Denso and Mitsubishi Electric declined to comment. The Commission can fine companies up to 10 percent of their global turnover for breaching antitrust rules. Commission spokesman Ricardo Cardoso declined to comment. U.S. antitrust regulators fined Hitachi Automotive Systems Ltd, Mitsubishi Electric Corp and others for fixing prices of accelerators and starters in September 2013. Japan's Fair Trade Commission in November 2012 also named the three companies in a similar cartel. The EU watchdog is investigating possible cartels in car thermal systems, car lighting, seat belts and steering wheels, car exhaust systems and electrolytic capacitors, among others.