The German transport ministry has ordered Mercedes-Benz to recall up to 774,000 cars across Europe after tests found that they contain unauthorised software, or a so-called defeat device, that could be used to manipulate diesel exhaust emissions.
In an official statement, the Kraftfahrt-Bundesamt (KBA) said it had ordered Mercedes to immediately recall selected Vito, C-Class and GLC models in Germany.
“The government will order 238,000 Daimler vehicles to be immediately recalled Germany wide because of unauthorised defeat devices,” the KBA said.
In the UK, Mercedes faces increasing pressure to recall the affected cars: “We are aware of the issue of ‘defeat devices’ in some Mercedes models and we are in communication with Mercedes-Benz UK about the matter. Mercedes have not yet notified us of an official recall so we are pressing them on this point and have given them until 22 June to respond,” said Ian Bartlett, head of DVSA’s vehicle safety branch and market surveillance unit.
Daimler is the parent company of Mercedes.
Among the models said to be affected are the 1.6-litre Vito 111 CDI and the 2.0-litre C220d and GLC 220d.
The KBA has not indicated the age of the cars involved, although officials suggest they include latest-generation models with Euro 6 emissions certification.
News of the recall comes after the German transport minister, Andreas Scheuer, met with Mercedes chairman Dieter Zetsche in Berlin to discuss what has been described as “irregularities in independent test results of various Mercedes-Benz models featuring the German car maker’s turbocharged four-cylinder diesel engine”.
Among the features brought into question by the KBA is software used to regulate the amount of Ad Blue solution injected into the SCR filter on the models in question.
Following the discussion, Scheuer said Daimler had pledged to remove the suspect software and co-operate with authorities.
Autocar understands that the software is programmed to lower the amount of Ad Blue being injected after a prescribed time. This lowers the efficiency of the SCR filter and leads to much higher nitrogen oxide emissions in real-world driving conditions than those claimed by Mercedes under test conditions.
A report in German newspaper Bild am Sonntag suggests the German Transport Ministry has identified up to five illegal Ad Blue and/or SCR switch off functions in various Mercedes-Benz diesel models.