Germany raised doubts about the legality of devices General Motors Co.'s Opel unit used to monitor emissions, raising the possibility that the brand's engine software breaches the country's regulations.
"Shut-off devices are fundamentally illegal, unless it is truly necessary to safeguard the engine," Transport Minister Alexander Dobrindt told reporters in Berlin on Wednesday after meeting with Opel chief Karl-Thomas Neumann and other officials from the GM division. "Therefore it's clear that in this situation, we have our doubts."
While Dobrindt says Opel acknowledged that software shut off emissions controls at high speeds, the automaker insisted it did so only to protect the car's engine and that everything it's done is within the law. Germany has given Opel, which agreed to cooperate with the probe, 14 days to provide more information.
The automaker has disputed results of a joint investigation by Spiegel magazine, ARD television's Monitor program and the Deutsche Umwelthilfe environmentalist group that found software in Zafira compact vans and Insignia sedans cut off emission controls under certain conditions, such as speeds exceeding 90 miles (145 kilometers) per hour.
The conclusions are "wrong," Neumann said Tuesday in a statement. "We at Opel don't have any illegal software."
Opel said in a statement e-mailed after Dobrindt's comments that the carmaker is fully supporting the government's investigations. It's engines are in line with laws and rules and no illegal software is used, the company said.
"It was clear with the already discernible differing legal assessments, that we would also reach different appraisals of the technical matters," Dobrindt said of the discussions on Wednesday with Opel.
The auto industry's credibility has been strained following Volkswagen AG's September admission that it rigged diesel-engine software to pass official tests, prompting Germany to set up an investigating commission.
Mitsubishi Motors Corp. has since acknowledged that it manipulated fuel-economy tests, and Daimler AG is checking for possible irregularities in its vehicle certifications at the behest of the U.S. Department of Justice.
Last month, Opel was among auto manufacturers that agreed with German authorities to voluntarily upgrade 630,000 vehicles in Europe to fix temperature-control setups that pushed the boundaries of regulation.
At the time, Dobrindt said a review hadn't found that other car models used a defeat device similar to Volkswagen's program. The minister said on Friday that the commission is also looking into reported emissions irregularities at Fiat Chrysler Automobiles NV.
Dobrindt said Wednesday that investigation will continue and that he'll also ask other automakers if they used devices similar to Opel.