Yes and it was widely known at the time that they were specifically being targeted while most manufacturers were using defeat devices because they were outcompeting American auto makers.
They knew that when doing the testing, the car would be on a rolling road inside, and usually when they do that they have the car doors open to let air go into the cabin and to talk to people etc.
So they programmed in a rule that "if the car is doing 100kph, and the door is open, change engine map to use more fuel and output less emissions".
Because it was extremely unlikely someone would have the car door open and doing 100kph in any other circumstances.
The company does not admit wrongdoing and says no one in the company acted in bad faith, said Jon Mills, a spokesperson for Cummins Inc. in an email to USA TODAY.
Cummins Inc. allegedly installed defeat devices on the engines of hundreds of thousands of 2013 to 20199 RAM 2500 and 3500 pickup trucks, according to the Department of Justice. The DOJ also says the company installed defeat devices on the engines of 330,000 newer RAM pickup trucks.
USA here. Can we please just start taxing fuel appropriately and remove subsidies? If fuel just cost what it actually costs (like the EU) then most of the problem goes away because only people who actually get work done with their truck's will afford to run them and only while getting a job done. Currently 2/3 of the heavy duty trucks I see are grocery haulers for little boys.