The companies deny the allegations.
Was Volkswagen alone in cheating on diesel emissions tests? The researchers who initially uncovered Dieselgate now allege that's not the case.
A team of scientists led by chemist Axel Friedrich presented the results of a new emissions analysis earlier this week in Berlin. The data apparently demonstrates that Mercedes and BMW also manipulated vehicle emissions values in order to meet legal limits, just as Volkswagen admitted doing.
The Mercedes C-Class is supposedly affected. The researchers, who are associated with an environmental group, say the C200 CDI diesel model apparently had more than double the legal limit of nitrogen oxide, or NOx, during test drives.
Daimler-AG, which owns Mercedes, has called the results "questionable."
The inspections, which were done in Switzerland, also reportedly showed abnormalities with a BMW 320d and a VW Passat 2.0 TDI. According to a report from German state television ZDF (link in German) these diesel engines produced higher NOx emissions than official testing had previously shown.
BMW claims the abnormalities may be due to different conditions in the lab and on the road and denied the accusations of impropriety, according to Frontal 21 (link in German). "There are no manipulations within BMW group," the statement says in German. "Our cars do not perform differently when on the road or in a test setting in the lab."
These are serious allegations, as it was Axel Friedrich's organisation ICCT and a few American researchers' tenacity that prompted the EPA investigation into Volkswagen over hidden software that manipulated emissions test results.
The experts believe they can prove that both Mercedes and BMW manipulated emissions tests
ICCT and researchers from West Virginia University were the first to show the discrepancy between official test results and the actual emissions while driving on the road, thanks to mobile testing devices. This led to the EPA investigation and its announcement of a notice of violation of the Clean Air Act by Volkswagen in September of this year.
Mercedes and BMW could possibly face a similar public relation crises and run into market turbulence the way Volkswagen did. After the VW scandal was made public, the company's share price plummeted. Volkswagen also faces substantial financial penalties, with officials from Maryland Governor Larry Hogan to environmental groups from China now calling for repercussions. The EPA warned that the German automaker could be looking at penalties of up to $18 billion in the US alone.
Other manufacturers have been in the scientists' and experts' sights for a while now, however.
"Trucks and 18-wheelers today are showing considerably fewer emissions than cars," said Friedrich, who worked for a German environmental agency before he became an independent researcher and activist.
This isn't the first time Friedrich's team, aided by the environmental group Deutsche Umwelthilfe, has presented measurements that suggest testing result manipulations at other manufacturers, either. In November, for example, they published data a Renault Espace, whose emissions were supposedly increased 13 to 25 times the norm. (Renault denied the allegations.)
On Wednesday, Friedrich, Jürgen Resch from Deutsche Umwelthilfe (German Environmental Relief), and attorney Remo Klinger presented their findings at the podium of Bundespressekonferenz (Federal Press Conference) in Berlin.
The experts believe they can prove that both Mercedes and BMW manipulated emissions tests. The Mercedes they tested was able to stay within legal limits when it was prepared for the test and had a warm engine, they said, but with a cold engine and no preparations, it showed considerably higher emissions values—hinting at how Mercedes might have avoided detection in official testing environments.
"We decisively reject speculations and interpretations that possible deviations between measurements taken on a stand in comparison to normal vehicle operation can only be attributed to manipulation," Mercedes-Benz said in a statement to Focus Online (link in German).
For Friedrich, it's nevertheless been clear for a while that the VW scandal and his findings reflect an underlying problem. "It's not a problem that's affecting VW or Daimler, it's a general phenomenon," he said.