By Viktoria Dendrinou

BRUSSELS--The European Commission started legal action Thursday against seven countries, including the U.K. and Germany, for failing to catch--or punish--car manufacturers cheating in emissions tests.

The commission, the European Union's executive arm, took action against the U.K., Germany, Spain, Czech Republic, Greece, Lithuania and Luxembourg, for failing to establish penalties systems to deter car manufacturers from violating emissions legislation, or for not applying sanctions when the law was breached.

The move, which was widely anticipated, came after the commission said manufacturers were understating their cars' emissions.

"Abiding by the law is first and foremost the duty of car manufacturers. But national authorities across the EU must ensure that car manufacturers actually comply with the law," said Elzbieta Bienkowska, the EU's internal market and industry commissioner.

Volkswagen AG admitted in 2015 that it rigged diesel engines on 11 million cars to cheat on checks for harmful nitrogen oxide emissions.

Subsequent investigations in Germany and other EU countries showed that several manufacturers were using loopholes in an EU ban on so-called defeat devices to understate their vehicles' emissions.

The commission said the Czech Republic, Greece and Lithuania had failed to introduce sanctions for emissions violation into their national law. It said Germany, Luxembourg, Spain and the U.K.--countries that issued type approvals for Volkswagen--hadn't applied penalties against the car maker, "despite the company's use of illegal defeat device software."

The commission also said that Germany and the U.K. broke the law by refusing to disclose information on potential emissions irregularities in Volkswagen and other cars.

A German investigation of manufacturers that included Volkswagen, BMW, Daimler, GM Opel, Ford, Fiat and Renault, found that only Volkswagen actively used software to recognize when its diesel-powered cars were being tested for emissions in order to cheat on the tests. Germany's KBA motor vehicle association, which conducted the tests, determined that Volkswagen's software could be considered an illegal defeat device under European law. The German government did not press charges against Volkswagen.

While the German study singled out Volkswagen for use of a defeat device, it also found that nearly all manufacturers used a loophole in regulations that allowed them to greatly reduce emissions controls if the outside temperature was too cold, in order to protect the engine. The study found that this so-called thermal window was so broadly defined that most manufacturers were able to legally produce higher noxious tailpipe emissions than generally allowed.

BMW, Daimler, GM, Ford, Fiat and Renault have denied using defeat devices. Volkswagen has repeatedly said that its software wasn't a defeat device as defined by European law.

Thursday's action is the first step of the commission's procedure for national infringements. Governments have two months to respond, after which Brussels can decide to refer them to the EU's top court, the European Court of Justice, in a process that can eventually lead to sanctions.

--William Boston contributed to this article.

Write to Viktoria Dendrinou at viktoria.dendrinou@wsj.com

(END) Dow Jones Newswires

December 08, 2016 07:51 ET (12:51 GMT)