Lawsuit Accuses GM of Using Defeat Devices in Duramax Diesel Pickups

Matt Posky
by Matt Posky
lawsuit accuses gm of using defeat devices in duramax diesel pickups

Suing automakers over diesel emissions violations is quickly on its way to becoming passé.

Since Volkswagen admitted to installing software that circumvented pollution laws, regulators have been on the hunt for their next big target. While it might make their efforts seem like a bit of a witch hunt, there’s good reason to be on the lookout. Studies have shown diesel emission levels are often much higher than analysts expected, with experts attributing the results to the high probability that other automakers are skirting regulatory guidelines — likely by way of defeat devices.

Daimler, Renault, and PSA Group are all being investigated in their home countries as FCA faces legal action within the United States.

General Motors is now being sued for allegedly installing defeat devices in its trucks to sidestep emissions tests, making it the sixth major manufacturer accused of diesel cheating since 2015. However, General Motors isn’t dabbling in gray areas, acting confused, or assuring the public it will get to the bottom of the accusations. It says the claims against it are flat out wrong.

Pat Morrissey, director of corporate communications at GM, issued a concise two-sentence response after news of the lawsuit broke. “These claims are baseless and we will vigorously defend ourselves,” Pat Morrissey stated. “The Duramax Diesel Chevrolet Silverado and GMC Sierra comply with all U.S. EPA and CARB emissions regulations.”

Owners and lessees of some 705,000 pickups powered by Duramax diesels filed a class-action lawsuit on Thursday, claiming GM had installed defeat devices in Chevrolet Silverados and GMC Sierras from 2011 through 2016. According to Bloomberg, it’s their assertion that the automaker misrepresented the Duramax’s abilities and that the system produces two to five times the legal limit of pollutants under normal driving conditions.

“GM claimed its engineers had accomplished a remarkable reduction of diesel emissions,” attorney Steve Berman said in the formal complaint. “These GM trucks likely dumped as much excess poisonous emissions into our air as did the cheating Volkswagen passenger cars.”

Berman is also currently representing drivers and dealerships in the litigation against FCA and previously went up against Volkswagen before it was slapped with $24.5 billion worth of penalties, fines, and vehicle recalls. Another similar thread between the cases is the inclusion of German auto supplier Bosch.

In the case against General Motors, Bosch is named as a defendant involved in the installation of three separate defeat devices, particularly those relating to the emission of nitrogen oxide pollutants. However, GM has already disclosed numerous on-board devices that help mitigate NOx levels, all of which have received EPA approval. Among the most noteworthy are the Duramax’s selective catalyst reduction system and treated diesel exhaust fluid (DEF), both of which serve to reduce NOx emissions. Both are standard items on modern diesel trucks and have proven to be one of the better ways to adhere to emissions guidelines without sacrificing performance.

As the name suggests, the catalyst reduction system is selective and not perpetually active — meaning there are occasions where emission levels can fluctuate outside of prescribed levels (when the vehicle is warming up, for example). Adequate levels of DEF are also required for the process to convert NOx into nitrogen gas and water. Without it, the truck’s computer eventually forces it to run in a more lethargic mode and may eventually forbid the vehicle from restarting.

In addition to this, Duramax-powered vehicles have a Regen mode that serves to burn off soot accumulated in the diesel particulate filter (DPF). During the process, fuel is injected into the exhaust in order to raise exhaust gas temperatures high enough to clear the DPF.

[Image: General Motors]

Join the conversation
3 of 21 comments
  • Fun2drive Fun2drive on May 26, 2017

    There is a big difference between actively defeating emissions controls (VW) and trying to keep close to the emissions limits (FCA has reported that was what they targeted). Now the lawyer community can smell a big payday to just have their complaints go away. There can be no doubt that this community of lawyers will be trying to gather diesel owners of every make and do the same thing. I expect ford, BMW and any other maker to get hit with these suits regardless of their merit and evidence. That is the key. Used to be that a complaint had to have credible evidence which so far regarding FCA and GM now with others coming soon there isn't any. That under the legal system constitutes a frivolous lawsuit when judges actually used judgement. Regarding Bosch. This is a joke Bosch supplies the auxiliary emissions devices and the manufacturer does the programming. How are they at fault? They have no control over how their devices are used. Ridiculous. By the way there is no evidence that the emissions levels used by the EPA which is a derivative of CARB are based on scientific evidence but typical California hysteria...........

    • DenverMike DenverMike on May 27, 2017

      "...typical California hysteria………". No "VW style" cheating here. Figure they caught FCA and GM on technicalities. "Defeat devices" do need to be "disclosed", but are designed-in to protect the engine from damage under some conditions, or override the minimum "standard", say when the vehicle runs out of urea fluid, and the driver keeps on driving. California is more (financially) broke than "hysterical", but yeah. Follow the (fines) money.

  • Kurkosdr Kurkosdr on May 28, 2017

    That is one ugly-ass truck.

  • FreedMike Well, good to see folks got their five minutes anti-Biden hate on. Glad he didn't do something REALLY hateful, like wearing a tan suit. Meanwhile, speaking of "picket lines," I seem to remember one that the former president - who's running again - attended. Now, the date escapes me...oh, wait, now I remember, it was on January 6th, 2021. But that was locker room talk, I suppose.
  • MaintenanceCosts 0-60 in four seconds and only ~0.65 g of cornering grip are not a good combination.As someone who has been absolutely terrified riding in a "regular" current-gen Escalade with the 6.2 and the most aggressive airport shuttle driver I've ever experienced, what the truck needs is NOT, NOT, more power. It needs better stability in transitions, where it always feels like you are on the cusp of losing the rear end.(We saw 110 mph on I-5 north of San Diego. My company fired the shuttle company after hearing of the experience.)
  • Analoggrotto Another victory for Kia Telluride.
  • MaintenanceCosts No surprise here. A turbocharged inline six is an efficient and smooth engine configuration if you can package it. And packaging isn't an issue in big pickups and SUVs.
  • Oberkanone To V or not to V. If you going to own a Cadillac then you must V.