The commission said that it and the German Cartel Office “have received information on this matter, which is currently being assessed by the commission.” The statement gave no details. “It is premature at this stage to speculate further,” the commission said.
Spokesmen for Volkswagen, Daimler and BMW declined to comment on Saturday. Volkswagen and Daimler have admitted some of the allegations to the authorities, according to Der Spiegel.
BMW, Daimler’s Mercedes-Benz unit and Volkswagen’s Audi and Porsche divisions dominate the global market for luxury cars, a crucial pillar of the German economy. Drivers around the world are willing to pay a premium for the German brands because of their reputation for precision and craftsmanship.
“Since the diesel scandal began two years ago trust in the German auto industry has been sinking on a daily basis,” Ferdinand Dudenhöffer, a professor at the University of Duisburg-Essen who follows the industry, said in an email on Saturday. “Diesel was the Germans’ great innovation, but it’s beyond rescue.”
The crisis has also taken on political dimensions. Chancellor Angela Merkel has tried to distance herself from the auto industry amid criticism that her government has lobbied for lax European emissions regulations that contributed to the scandal.
“The diesel scandal came about because our politicians passed bad laws,” Mr. Dudenhöffer said.
The broad conspiracy described by Der Spiegel included dozens of working committees that discussed how to limit competition on new technologies, including emissions systems.
Though allegations of collusion are new, it was already clear that vehicles sold by almost all carmakers in Europe pollute more in everyday use than in tests. As a result, levels of harmful nitrogen oxides are higher in urban areas than they would be if carmakers were adhering to pollution standards.
Studies last year by the British, French and German governments found that carmakers exploited gaping loopholes in European Union regulations to evade emissions standards. For example, many reduced pollution controls at temperatures below 68 degrees Fahrenheit, supposedly to protect engines from damage.
Regulators did not notice because they only test cars at temperatures above 68 degrees.
Some of the allegations contained in the Spiegel report fit in with what is already known about Volkswagen’s cheating.
In 2006, according to the magazine, the German carmakers agreed to limit the size of the tanks used to hold a chemical solution that helps neutralize diesel emissions. Volkswagen and its Audi division have previously admitted in court documents that the tanks they installed in their cars did not hold enough of the solution, known as AdBlue, to last between oil changes. The company did not want the tanks to take space from the cars’ sound systems, according to a criminal complaint against an Audi engineer filed earlier this month in the United States.
Rather than install bigger tanks, Volkswagen and Audi illegally programmed cars to ration the chemical solution — and produce excess emissions — except when engine software detected that an official test was underway.
While only Volkswagen and Audi have admitted wrongdoing, all the main German carmakers have acknowledged that their vehicles may produce excess levels of nitrogen oxides during everyday driving.
On Friday, Audi followed Daimler and BMW in announcing plans to upgrade software on diesel vehicles across Europe to reduce emissions.