FRANKFURT, Germany — BMW, responding Sunday to claims it formed a cartel with Daimler and Volkswagen to hold down the prices of crucial technology, denied that the German carmakers had agreed among themselves to install emissions equipment that was inadequate to do the job.
The statement by BMW was the first attempt at damage control by the carmakers since the European Commission said Saturday it was investigating accusations of illegal collusion among them.
The German carmakers, who dominate the global market for luxury cars, can hardly afford another blow to their reputations. They were under fire after government studies showed that diesel cars, once promoted as environmentally friendly, frequently pollute much more than advertised.
Adding to the pressure, the accusations against the automakers showed signs Sunday of becoming an issue in coming national elections. Chancellor Angela Merkel and her transport minister, Alexander Dobrindt, faced increasing criticism that they had been overly accommodating to the carmakers.
Martin Schulz, the chancellor candidate for the left-leaning Social Democrats, said that if the allegations proved true, “it would be a gigantic fraud against customers,” according to news reports.
Such harsh criticism of the auto industry is unusual in Germany, and it illustrates the degree to which public opinion is turning against the carmakers. Motor vehicles are the country’s biggest export, and Volkswagen, Daimler, and BMW are among Germany’s largest employers.
In its statement Sunday, BMW said discussions with the other carmakers had been about how to ensure that customers would be able to buy refills of a chemical needed for pollution equipment in diesel vehicles. The chemical, a urea solution sold commercially as AdBlue, is sprayed into the exhaust to neutralize harmful nitrogen oxides.
German magazine Der Spiegel reported Friday that the carmakers agreed in 2006 to limit the size of the tanks used to hold AdBlue to save space in the car. Der Spiegel said it had seen documents that were part of an antitrust investigation.
BMW said its latest models were clean, despite a relatively small AdBlue tank, because they combined two types of pollution technology: a system that uses the AdBlue spray and a separate catalytic converter that traps nitrogen oxide molecules.
In a tacit admission that older vehicles pollute too much, Daimler, Volkswagen’s Audi division, and BMW have announced plans to upgrade software on diesel vehicles across Europe to reduce emissions. The three carmakers have said in recent days that they will modify more than 4 million vehicles, including 3 million Daimler vehicles.