Regulators Probe Mercedes for Possible Emissions Cheating

Mercedes-Benz BlueTEC diesel badge.jpg Mercedes-Benz Bluetec diesel badge | Manufacturer image

CARS.COM — Regulators may have found illegal emissions software in Mercedes-Benz diesel vehicles, according to a new report. Citing private documents, German newspaper Bild am Sonntag reports U.S. investigators have found programs within the German automaker’s diesel vehicles that thwart emissions tests, according to Bloomberg.

Related: Mercedes-Benz Gives Up on 2017 Diesels

Citing the newspaper, Automotive News says the functions, which have names like “Slipguard” and “Bit 15,” switched off emissions controls after 16 miles of driving or intuited whether cars were under laboratory tests. Some software altered how much diesel exhaust-treatment fluid to apply, and some diesel vehicles emitted nitrogen oxide — the smog-forming pollutant at the heart of the Volkswagen Group’s diesel scandal — at up to 10 times the legal levels, according to Automotive News.

In the wake of Volkswagen’s crisis, which affects nearly 600,000 U.S. cars from the 2009-16 model years, U.S. regulators have scrutinized other automakers with diesel vehicles, including Fiat Chrysler Automobiles and Mercedes-Benz. After efforts stalled to secure EPA certification on its 2017 model-year diesel cars (called Bluetec), Mercedes stopped plans to sell diesel cars here.

Asked for comment, Mercedes spokesman Christian Bokich released a company statement to that says the documents Bilt am Sonntag reviewed “have obviously selectively been released in order to harm Daimler and its 290,000 employees.” (Daimler AG is the parent company of Mercedes-Benz.)

“We have been fully cooperating with the U.S. authorities for more than two years and have provided comprehensive transparency,” the statement says. “The authorities know the documents and no complaint has been filed. We will not comment on further details of the ongoing investigation as we have agreed upon strict confidentiality with [the] U.S. Department of Justice.”

In Daimler’s annual report released this month, the automaker said it remains “convinced that diesel engines will continue to be a firm element of the drive-system mix” but said it’s still under diesel-related investigation by the Department of Justice, EPA, California Air Resources Board, Securities and Exchange Commission, and certain individual states, in addition to various international bodies.

The report goes on to note that violation notices and related complaints filed by U.S. authorities against another vehicle manufacturer in early 2017 (unnamed in the report, but likely FCA) identified certain functions “common in diesel vehicles” as “impermissible” auxiliary emissions-control devices. In Volkswagen’s case, some so-called AECDs constituted illegal defeat devices.

“In light of the ongoing governmental information requests, inquiries and investigations, and our own internal investigation, it cannot be ruled out that the various authorities might reach the conclusion that Mercedes-Benz diesel vehicles have similar functionalities,” the report said.

The Department of Justice and EPA did not immediately respond to’s requests for comment. Asked if the automaker plans to resume diesel car sales in the U.S. anytime soon, Mercedes’ Bokich declined comment.’s Editorial department is your source for automotive news and reviews. In line with’s long-standing ethics policy, editors and reviewers don’t accept gifts or free trips from automakers. The Editorial department is independent of’s advertising, sales and sponsored content departments.

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