German officials were surprised to see how many diesel cars that it tested showed extremely high CO2 emissions.

A German government committee has asked for further tests on 30 cars it says have “inexplicably high” CO2 emissions. Testing in Germany for diesel cars with defeat-device software began with Volkswagen Group admitted to manipulating engine management software to cheat tests for the health-harming NOx pollutants.

The German government committee hasn’t revealed which cars have been tested in its new study. The committee will present a CO2 report following the results of these tests, a spokeswoman from the German transport ministry said.

“Out of 53 cars tested for illegal software, 30 were showing inexplicably high CO2 emissions. The experts are now looking into this,” the spokeswoman told Automotive News Europe.

Germany’s federal KBA motor transport authority said in November that it was testing cars from major automakers including VW Group brands, Ford, Opel, BMW, Mercedes-Benz, Fiat, Renault, Peugeot, and Toyota.

SEE ALSO: Opel Alleged to Be Using Defeat Devices in Germany

Last week Opel and Fiat were asked to appear before a German government commission to explain high NOx emissions from diesel versions of the Opel Zafira minivan and Fiat 500X. Opel did attend the hearing, but Fiat was criticized for not attending the meeting.

The KBA has found that only VW Group used a defeat device. The motor transport authority has been investigating techniques used by automakers with their own defeat devices to cover up accurate emissions reporting from their diesel vehicles.

Automotive News