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]

Most North Americans who buy diesels do so for virtue signalling. Irony bites again.
+1
I was a TDI owner bought mine new in 2011, and I would buy a MB diesel E class wagon if they still made them, and I can assure you BrandLoyalty there was no virtue Signaling when one drives a VW TDI wagon. And I doubt a MB diesel wagon would have any either ( compared to a gas MB wagon) Why did I buy one well I drive a ton per year ( 30,000 plus a year) they did very well on fuel in the real world VW said 42 MPG and I got about that in real world driving, and I got a ton of driving out of a tank. Now we all know why they could do that today but when I bought it new I had no clue. I test drove a gas VW wagon and there was no comparison vs the Oil burner. I doubt most North Americans , well really most in the USA even notice a diesel that was made in the last 10 years. They may all cheat I have no idea but your statement is not correct.
I, as well. With 30k per year, I felt like the gas station hose was in my wallet, sucking cash out. The TDi was a solid car, with VW seats, soundproofing like a vault, and the VW Sport suspension settings we don’t otherwise get in the US. It drove well, was comfortable even after a 300 mile day. I bought a big can of Cetane boost to deal with the crappy US diesel, which made a definite difference-this alone shows why the euro diesel experience is different than the US experience. I can’t say as I had any virtue signals here, other than I was getting 40 mpg without a Prius, or blocking traffic as I ‘hypermile’ my Prius. My DPF cracked too, a diverter valve in the exhaust broke (exposed return spring, would rust/jam) and sadly everything south of the turbo was junk. VW sent me checks, which was nice. I made up any alleged pollution virtue on this car with my two stroke Yamaha jet ski. Still sad about how it went, it was my third VW diesel. The other two were older, built like an anvil “clatter-wagons” but ran over 200k each. I still look at alternatives, but a Tesla is too expensive, the Bolt is too small, and only the 328d remains standing.
That’s your favorite phrase. Its perfect for you, judgemental and, yes, it in itself is virtue signalling.
Uh, what? Pretty sure most people buy them for the highway fuel economy, and how they drive. Certainly why I bought all of mine. Peugeot, Mercedes, and VW diesels.
Everyone that I know who drives a diesel does so for the torque (towing a travel trailer), fuel economy and engine durability. The downsides are smelly fueling, smelly exhaust and engine noise. I suspect the semi-truck-like noise is appealing to some people, though.
To claim that millions of people are “virtue signalling” is arrogant, judgmental and downright silly. If anything, diesel drivers seen as less than virtuous by the driver behind them inhaling that smell.
To assume that everyone is trying to project an image by their choice of car is erroneous. It’s just a car (or a truck), not a psychological tell-all.
I’m the least “green” person you know. I don’t do virtue signaling. I bought a TDI Jetta for 40mpg in a non-Prius. A failed turbo and DPF convinced me that the car was going to be a money pit and I dumped it. When the cheating scandal broke I didn’t feel cheated, only disappointed that I didn’t hold it long enough to cash in.
All those TDI owners are just wannabe flatbill bros that can’t afford a Powerstroke? Cool.
Sure, but so do the people who buy bro-dozers. They’re just signalling a different value.
It’s their money.
In the 80s my dad used to have an Olds Diesel 98 – reason the old man bought it was the fuel savings, not to save the planet. When driving 40k miles a year, he could actually turn a (very small) profit since the mileage reimbursements were made for 80s gasoline consumption.
Too bad it was such a shoddy engine since the rest of the car was nice.
I was seriously considering the VW TDI wagon until the emissions cheat news broke. Why? I like the idea of 40mpg+ on the highway.
Agreed. In the last 25-30 years, a diesel MB served no purpose other than to assuage the owner that there was a rational decision for buying the car. Doesn’t matter now, just proof that I am (or think I will be) a 1%-er.
When I was young, I actually knew a couple of families that bought a diesel MB and drove that sucker 500k miles!
Those days are gone.
Why are those days gone? Member at our church has over 400,000 on his diesel ML. Same engine and transmission.
Today’s required emissions tech, has made previously famously long-lasting-with little-care diesels, at best long-lasting-with-lots-of-expensive-care. Plus, more expensive to buy in the first place. And less frugal, vis-a-vis much improved in that regard gassers.
Diesel engines, at least the Cummins type truck ones, are still fundamentally solid for a huge number of miles. But there’s just so much more complex and expensive stuff hanging off them, that also need maintenance, as well as suck fuel.
@Stuki,
If modern Diesel engines are so unreliable then they wouldn‘t be the first choice for taxi, commercial and trucking fleets in my country. European trucks have the same and even more complex emissions-cleaning technology – and it must work fine since these vehicles are always on the move. The average European trucker will do anything from 80,000 – 130,000 km a year. When the truck is in the shop it is not making money. Companies are not interested in unreliable technology.
My brother owns a taxi business and he uses the last generation (with the quadratic headlights) and some older E-Klassen (the mid-1990s model and the one that came afterwards) from Mercredes, diesel, of course. The average taxi does anything from 40,000 to 60,000 km a year, sometimes more. Again, the engines are fine. Some of the older common-rail E-Klassen can develop injector issues at very high mileages, but what you might view as a reliability issue they view as normal wear and tear on a component that is in use 24 hours a day, 365 days a year at low and high speeds and in stop-and-go-traffic and so forth.
I myself own a used, high mileage Mercedes diesel from 2007 that was well-maintained and whose emissions components all work flawlessly.
OTR truck engines sees usage completely different from that of a passenger car. And one that heavily favors diesel. They’ve also generally been exempt from all manners of emissions regs that passenger cars are not. Not sure if that has changed in Europe over the past few years.
One taxi fleet, particularly one which developed experience with diesels back when they were conceptually simpler, hence likely more reliable, may have enough invested in diesel knowledge to sway things a bit, compared to someone starting from scratch. It’s also hard to untangle what regulations do to cost/benefit equations in venues as regulated as US and European passenger cars.
I’d suggest the makeup of the Uber fleet in US cities, is a better meter of the tco of a a diesel vs gas vs hybrid powertrain. US regs are at least a little more similar between diesel and gas than Europe’s (at least they were), differing fuel taxes skew things less; and the costs, including downtime, to an Uber owner/operator very much in his face and obvious. If diesel were the economic choice for high mileage passenger car duty, the Uber drivers would pick up on it.
Third world, no regulations, use, could be another good metric, but diesel in those places, is just not reliably clean enough for modern diesels to make it home from the dealer. If their computers allow them to start at all.
I remember those days.
Back when the three-pointed star assured you that you’d bought the world’s best car, and the DIESEL badge assured you that nobody’d ever steal it.
+1
+1
I was behind a W123 era M-B 300D Turbodiesel today. It was in very nice shape and the driver punched it as we merged onto another freeway. Not quite rolling coal, but lots of smoke every time the transmission shifted.
That. The old diesels always had dirty trunk lids because of the unburned bits and particulates. I was amazed the TDI still had a perfectly clean exhaust pipe up until the DPF cracked at 74k miles….which was very easy to see as the clean bright metal pipe was suddenly coated with the blackest dust I’d ever seen and suddenly the back of the car began to get dirty.
If MB got performance equal to that which VW needed a “cheat device” to obtain, MB also has a de facto “cheat device” in there. It’only a matter of how soft the knee-points are, and how obvious it is to the ambulance chasers that those are somehow related to known testing cycles. VW didn’t just put the stuff in there to be mean Germans bent on making people inhale poisonous gasses. Nor because their engineers are somehow meaningfully behind their neighbors in diesel tech, as it’s not as if it’s that hard to hire someone from MB to get them up to speed.
No no, you can always blame the Germans. For something.
Faking MPG, faking emissions, mishandling safety issues. It’s this 80 percent of the automakers that give the rest of the car industry a bad name.
Or a complete lack of perspective on just how “safe,” clean and fuel-efficient modern cars are.
“Most North Americans who buy diesels do so for virtue signalling. Irony bites again.”
Not necessarily. Pickup buyers choose them for power. Not much virtue signalling in a lifted 4X4 rolling coal. I bought the wife a ’13 Jetta tdi Wagon. Put down about 65K trouble free miles before we gave it to the kids. When gas was $4/gal, it made sense. (Maintenance is a little spendy, though. Typical German car in that respect). Kids liked it so much they bought a ’15 Golf tdi right after they were released for sale by the EPA. They both drive about 40K miles a year- 50+ mpg doesn’t need explanation, and they aren’t Prius people.
So many companies “cheating” on diesel emissions tests seems like proof that the standards are too tight.
Time to back off.
This.
I don’t have a diesel and don’t plan on buying any time soon, but it’s obvious the standards were intended as a defacto ban without calling it a ban. It’s like a 54 mpg CAFE mileage intended to serve as a ban on most gas powered cars without calling it a ban.
Exactly. See NY’s attempt at making a 7-round magazine limit for firearms; that banned 95% of all new firearms from being sold in the state. They backed off and made it 10 rounds, but I moved away to Texas so I couldn’t care less.
GM investigated multiple times, no findings of fault. They charge to the market what it costs to achieve compliance. Mazda has not brought their diesel to market because they can’t match compliance. They could have cheated.
Just stunning. Company breaks the law, the problem is the law, not ethics.
The more numerous the laws, the more corrupt the government.
Tactius
Laws must be set to statistically enforcible standards, e.g., speed limits. If too many people break those laws then the laws are not statistically sound in the first place and are not enforcible because of the unnecessarily large amount of societal resources needed to artificially uphold them.
That said, not sure just what percentage of manufacturers are breaking these laws. So far we have VW, FCA and MB.
Laws must be set to enforcible standards, e.g., speed limits. If too many people break those laws then the laws are not statistically sound in the first place and are not enforcible because of the unnecessarily large amount of societal resources needed to artificially uphold them.
That said, not sure just what percentage of manufacturers are breaking these laws. So far we have VW, FCA and MB.
Time to back off the standards or time to admit that diesel is dirty?
How dirty are these cars though? Do you suffocate every time you drive behind a Bluetec Mercedes? Can you even see any soot coming out? For resource conservation, it’s a remarkably clean fuel.
Remarkably clean? If that were the case, there wouldn’t be so many hoops for diesel to jump through to meet the same requirements as gasoline.
I don’t dislike diesel, but it’s not magic either.
Pollute at will. We’ll live.
Luxury euro-sedans are going to cheat where ever they can as they lose market share to large American luxury SUV/CUVs. They missed the boat and now trail the Americans and Japanese in this key segment. Things will get worse now that Subaru is entering the large SUV/CUV market, albeit not as a luxury entry.
Big money around here (Texas) ripping out Ford’s “Clean Diesel” tech (Ecoblue?) once it dies and leaves you in limp mode. Shops even specialize in it.
There was an article in the NY Times a few days back, about how a company buys tractors with no engines, refits an older engine rebuilt from a junkyard, and you have a new truck, with the older emissions rules. It’s a big business, and the result is that they are exploiting a loophole, but putting many older polluting trucks on the road “as new”. Makes the whole VW thing look silly now, but there was a reason so few diesels ever hit the US market..
@speedlaw. Not diesel related but similar to your comment. There was a bit of a scam in SoCal when I lived out there 30-odd years ago with re-VIN’ing new non-importable Mexican VW Beetles with VIN plates stripped from junked US Beetles. I briefly considered it so as to have an updated brand-new Beetle until I saw what the penalties were if caught.
The gray area trucks are called Gliders. One company got caught trying to buy research saying their older re built engines are as clean as the 2018 MY engines. Apparently a small university president was caught ram-rodding research past the engineering department without review so they could feed it to a congressman/Trump era EPA to maintain loopholes. Academic research drama in progress according to the media.
Just a matter of time before someone figures out what defeat devices are being used on full size diesel pickups. Hilarity will ensue.
I’m not surprised that MB may be caught in the same EPA snare that got VW. The emissions standards aren’t practical, and are a de facto ban, as has been said.
We chose the TDi version of our Q5 because it offered the best combination of performance and efficiency of the available powertrains. 0-60 in less than 6 seconds combined with passenger and cargo space and 31 mpg overall in 45K miles since new says it all.
We’ll miss it when it’s gone.
Dieselgate II, or III?
Now Toyo, Lexi, VW and others are ramping up electric only products in the near future. Where will all of the juice come from? Weren’t there concerns that the power grid could not handle too many more electrics?
Over regulation of everything! Cars, weed, guns and rental properties (my biz). Big brother need to stick it.
Plenty of electricity. Perhaps a limited number of materials like cobalt to build batteries with I read.
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.
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.