Own a 2011-2016 GMC Sierra Duramax Diesel 2500 HD or 3500 HD? The GMC Sierra diesel engine you paid a $5,000 premium for is allegedly equipped with three cheat devices that allow your vehicle to emit illegal levels of deadly NOx emissions. You may be entitled to compensation or a buyback. Fill out the form to find out your rights »

Case Status
U.S. District Court for the Eastern District of Michigan
Case Number
General Motors LLC
Robert Bosch GMBH
Robert Bosch LLC
File Date


  • 2011-2016 GMC Sierra Duramax Diesel 2500 HD
  • 2011-2016 GMC Sierra Duramax Diesel 3500 HD
  • Chevy Silverado »

Duramax Diesel Class Action Infographic

According to the firm's lawsuit, much like VW, Fiat Chrysler and Mercedes, GM has intentionally sold GMC Sierra Duramax Diesel 2500 HD and 3500 HD vehicles with emissions-cheating devices that mask the vehicle's release of illegally high levels of NOx. The use of these “defeat devices” means consumers paid a $5,000 premium for a diesel car that is, in fact, emitting illegal levels of deadly NOx emissions. GM knew consumers would pay more for a powerful and efficient diesel option, and used these devices to obtain the power and performance it wanted, while hiding illegal levels of pollution.

If you own an affected GMC Sierra, find out your consumer rights to compensation. Hagens Berman believes GM has scammed consumers into paying high premiums for what it told consumers were vehicles that were legal and operated within emissions limits.


According to our investigation, GM intentionally installed multiple emissions-cheating devices in affected GMC Sierra trucks, in violation of federal requirements. We believe GM was motivated by its desire to increase sales and profits, and without cheating emissions the Sierra trucks could not achieve the fuel economy, range, towing power or performance GM promised its customers. The emissions-cheating devices engage emissions controls at temperatures within which emissions tests must be done, but outside that temperature range emissions controls are turned down or “de-rated.” Another defeat device de-rates emissions controls after 5 to 10 minutes of steady (i.e., highway) driving, which never happens during an emissions test. These devices combine to allow the trucks to pass emissions tests while masking the vehicle's true output of NOx during actual on-road driving. 

Affected Sierra Duramax diesels exceed by two to five fold the Federal and California NOx emissions limits and cost an estimated $5,000 more than their gasoline equivalent.


Hagens Berman believes that consumers have the right to reimbursement for the premium price they paid for what they thought was a powerful, efficient and emissions-compliant option. According to the firm's investigation, GM charged consumers high prices for vehicles that are in fact emitting illegally high emissions, rendering them out of compliance with federal regulations. Simply put, thousands of consumers did not receive what they paid for, and purchased their Silverado under what we believe is false information.


Hagens Berman is one of the most successful auto litigation law firms in the U.S. and is presently leading nationwide cases against Volkswagen, GM, Mercedes and Fiat Chrysler for use of diesel emissions-cheating software. Our firm’s independent research outpaces even government agencies, and we are the only firm dedicating its own resources to uncovering new instances of fraud. Hagens Berman has also taken on other automakers on behalf of consumers throughout the United States for safety defects and negligence, and your claim will be handled by attorneys experienced in automotive consumer law.


There is no cost or fee whatsoever involved in joining this action. In the event Hagens Berman or any other firm obtains a settlement that provides benefits to class members, the court will decide a reasonable fee to be awarded to the class' legal team. In no case will any class member ever be asked to pay any out-of-pocket sum.


Amended Complaint Filed

Hagens Berman filed an amended complaint against General Motors highlighting new details about the cheat and involvement of Bosch.

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