Volvo, Renault, Mercedes, Jeep, Hyundai, Citroen, BMW, Mazda, Fiat, Ford and Peugeot have not used fraud to pass the tests. You are citing studies using different test conditions than the official test.
But to say that the manufacturers have no fault in the way the tests are structured is a bit... disingenuous. Don't you think?
But There's a big difference between the company that make engineering decisions that try to improve the results on the benchmark (because after all that's what consumers get fooled with) and the one that would have a "if (benchmark_in_progress) cheat; "