Whoops: Mercedes-Benz Diesel Probe in U.S. Uncovers Possible Defeat Device

Matt Posky
by Matt Posky
whoops mercedes benz diesel probe in u s uncovers possible defeat device

U.S. investigators have found what could be illegal software modifications on Mercedes-Benz diesels intended to help the vehicles pass emissions testing. An engine management function called Slipguard recognized whether the car was undergoing testing procedures while another, called Bit 15, halted emissions cleaning after roughly 16 miles of driving. Together, the two pieces of software may amount to what is known within the industry as a “defeat device.”

When paired the software apparently enabled the cars to produce NOx levels up to 10 times higher than what is legally permitted. Interestingly, Mercedes-Benz issued a voluntary recall upon roughly 3 million European cars last month to reduce nitrogen oxide emissions by tweaking their electronic control units.

German media outlet Bild am Sonntag, has also cited confidential emails between Mercedes’ engineers that questioned whether the software functions were legal to use. Daimler has been under pressure in the diesel exhaust scandal for some time. Stuttgart prosecutors and the U.S. Department of Justice have both been investigating the issue since the spring of 2017.

A company spokesman declined to elaborate on the documents, saying the automaker was cooperating with the U.S. authorities and had agreed upon strict confidentiality with the Department of Justice. “The authorities know the documents and no complaint has been filed,” a spokesman told Automotive News. “The documents available to Bild have obviously selectively been released in order to harm Daimler and its 290,000 employees … We have been fully cooperating for more than two years and provide comprehensive transparency.”

Daimler CEO Dieter Zetsche has repeatedly emphasized, since the outbreak of Volkswagen’s diesel sandal over two years ago, that vehicles from Mercedes-Benz had not and would not be manipulated.

[Image: Mercedes-Benz]

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  • Land Ark Land Ark on Feb 19, 2018

    I always suspected that no other manufacturer called out VW for their cheat devices before the private company did because they were [mostly] all doing it. Everyone was baffled by how VW was able to get the numbers that they did. You can't tell me someone didn't reverse engineer a car and figure it out. Also suspiciously absent were other car makers trying to lure customers to them assuaging that their clean diesel was actually clean.

  • MercedesDieselGuy72 MercedesDieselGuy72 on Feb 19, 2018

    Rude comments above aside, I've owned several M-B diesels, several of which went well past 300K miles, one that went to just under 500K before being totaled in a street flood. Currently in one of the apparently cheating E250 Bluetec 4-matic. I buy them because they get great mileage, are very very comfortable, I travel long distances often, and the Diesel engines last much longer. I am disappointed about this news, but... I will drive them until I cannot.

  • ToolGuy Here is an interesting graphic, if you're into that sort of thing.
  • ToolGuy Nice website you got there (even the glitches have glitches)
  • Namesakeone Actually, per the IIHS ratings, "Acceptable" is second best, not second worst. The ratings are "Good," "Acceptable," "Marginal" and "Poor."
  • Inside Looking Out "And safety was enhanced generally via new reversing lamps and turn signals fitted as standard equipment."Did not get it, turn signals were optional in 1954?
  • Lorenzo As long as Grenadier is just a name, and it doesn't actually grenade like Chrysler UltraDrive transmissions. Still, how big is the market for grossly overpriced vehicles? A name like INEOS doesn't have the snobbobile cachet yet. The bulk of the auto market is people who need a reliable, economical car to get to work, and they're not going to pay these prices.