While Volkswagen has received approval from U.S. and European authorities to take some steps to address diesel cars with emissions-cheating "defeat device" software, the diesel scandal is still expanding.

A German probe into whether VW should have notified investors of the "defeat devices" earlier now includes the chairman of the company's supervisory board.

Public prosecutors in Braunschweig, Germany, recently expanded their probe to include chair Hans Dieter Pötsch, who was VW Group CFO when the diesel scandal broke last year, reports the Financial Times.

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A Volkswagen statement on Pötsch's inclusion said that the company "reaffirms its belief that the Volkswagen Board of Management its disclosure obligation under German capital markets law."

The investigation focuses on when VW admitted to the public that it used "defeat devices," which allowed TDI diesel models to circumvent U.S. emissions standards.

This was made public by the U.S. Environmental Protection Agency (EPA) in a press conference on September 28, 2015.

2010 Volkswagen Golf TDI

2010 Volkswagen Golf TDI

But Volkswagen notified the EPA and California Air Resources Board (CARB) of the "defeat devices" on September 3.

Investors have argued that, under German disclosure laws, VW should have informed them at the earlier date because of the potential impact on their investments.

In June, the Braunschweig prosecutor's officelocated near Volkswagen's headquarters—said there were "sufficient factual indications" that Volkswagen should have disclosed the existence of "defeat devices" at an earlier date.

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Last week, the government of Lower SaxonyVW's home state and its second-largest shareholder—was also critical of the company.

In response to a Volkswagen statement that use of "defeat device" software did not violate German law, state premier Stephan Weil's office called the use of said software "inexcusable."

Weil's office said it was "indisputable" that the software allowed cars to produce higher levels of emissions on the road than in laboratory testing.

2010 Volkswagen Golf TDI

2010 Volkswagen Golf TDI

The statement came as Volkswagen received approval from the German KBA motor-vehicle authority for emissions-related modifications on an additional group of diesel cars.

The KBA previously approved modifications for around 5.6 million models in Europe with 1.2-liter and 2.0-liter engines.

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These models required only software changes to meet the KBA's approval.

Newly-approved modifications for cars with 1.6-liter engines include both software changes and a mesh, to be installed near the air filter.

All modifications approved by the KBA apply to models sold across Europe.


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