BRUSSELS (AP) — European Union regulators have opened an in-depth investigation into whether automakers BMW, Daimler and Volkswagen colluded to limit the development and roll-out of car emission control systems.

The EU Commission said Tuesday that it had received information that BMW, Daimler, Volkswagen, and VW units Audi and Porsche held meetings to discuss clean technologies aimed at limiting car exhaust emissions.

The probe focuses on whether the automakers agreed not to compete against each other in developing and introducing technology to restrict pollution from gasoline and diesel passe...