I'm not fluent on the diesel emissions situation-. Pure gut speculation leads me to wonder were these manufacturers holistically cheating or technically cheating. There is a large difference between the two. Kind of like income taxes, if you have a complex tax situation, it is likely easy to technically make a error on the taxes, as simple as rounding down when one should round up. Rounding up or rounding down likely made no material difference in the final tax owed figure, but technically one could be identified as tax cheating. Did the manufacturers truly and willfully publish fake emissions numbers/ statistics? Or is the issue an interpretation of the published standards? I have no idea.
In a nutshell, both VW and Cummins created primary and secondary emissions control programs which lied to the EPA when being tested. I'm not up to snuff on the dets of the Cummins story yet, but I can speak to the VW story.
VW wrote programming into their ECMs that essentially ran two different programs; one for passing the test, and one for daily driving (far worse emissions). Typically, vehicles are tested in stationary cells; essentially like a dynamometer for chassis (like you'd see HP and Torque runs). So, when those test systems are running, the cars are stationary and the drive wheels are moving. So it's an easy cheat ... you have the ECM monitor the wheels and various control modules, and then select a program for street or test mode.
Example for VW; a FWD car with diesel engine:
1 - if the front wheels are turning above 10mph, and the rear wheels are not turning at all, it presumes that it's on a "test" bed. The ECM can also monitor if something is hooked up to the OBDII circuits, etc. It uses all these inputs to determine if the vehicle is being "tested" for emissions. So if it determines it's being tested, it then runs the "clean" ECM emissions program. The car won't put out the certified power or have the throttle response that customers want, but the EPA neither cares about or tests the HP and Torque claims; they only care about clean air. So to pass the emissions tests, they run detuned programs based on the fact that the car is in a stationary test mode.
2 - if all wheels are turning and nothing is hooked up to the various module ports, the ECM assumes it's being driven on the street, and will provide the rated HP and torque numbers and throttle response, but it won't make the mandated emissions levels.
Hence, VW purposely purposely cheated by creating two ECM programs loaded into each and every TDI sold; one for passing the emissions tests, and one for daily driving. This wasn't any form of an accident or "technical" cheat. It was a flat out, "we're going to purposely violate the rules" by having two internal engine programs, depending upon whether or not they were being "sniffed" at the tailpipe.
As far as I can tell with Cummins, it was something similar; they installed "defeat devices" which obviously could determine if a "test" was being run. When tested, it ran the "clean" program. When being daily-driven, it would defeat the clean program and revert to a more powerful (but dirty emissions) program. I'm just not up fully on the dets. Because Ram wasn't directly fined or implicated, I would make the presumption that Cummins did this without Ram's knowledge. Otherwise Ram would also be involved directly. Sure - Ram will have to be the service point of contact for the program updates, but I don't think the costs fall upon Ram, at least at this time. And Cummins was doing it for 10 years! (2013 - 2023).
This is what really pisses me off, and why I will never trust Cummins ... (and VW, as they essentially took the "not my fault" approach)
Here is a quote from an article regarding Cummins:
In a statement, Cummins said it did not admit any wrongdoing and that it had no evidence its employees acted in bad faith.
Didn't act in bad faith? Are you flippin' kidding me? Am I supposed to believe that somehow, in some magical way, two programs got written into code, and loaded into 600K vehicle engine ECMs, and it was an innocent accident? An accident that perfectly mated 2 non-dependent ECM programs in such a manner that they can meet the necessary emission limits on one side, and yet also produced HP and torque numbers for the purpose of competitive truck-sales marketing? I'm supposed to be so gullible that I don't think that after hundreds of hours of engine testing, no one noticed this "Dr. Jekyll / Mr. Hyde" program personality? That the engineers and managers at Cummins didn't understand why there were so many lines of code, and such different disparity performance vs emissions? And I'm sure that all the people who signed off the test results had no idea why two ECM programs exist inside the same little black box? As if there was one lone programmer who innocently made a mistake by having two unique programs that just coincidentally ran low emission on one side, and superior HP and torque on the other side, and it was just a lone-wolf fluke mistake?
VW just got caught doing a very similar thing a few years before Cummins was caught. Given that Cummins was doing it for 10 years, I bet they were quietly crapping their pants, fearing the worst. And it happened; they got caught.
Wanna know who really gets screwed? The customer and the investors. Cummins will take a big hit against revenues and write off that $2B in fines and fixes; Cummins won't pay out dividends or buy back stock. Further, that's $2B they won't be able to put into new engine developments, won't purchase new equipment, won't give employee raises, won't develop customer satisfaction campaigns, won't be able to spend on other warranty claims, etc, etc, etc.
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As I said, I cannot tell you why Ford isn't involved with any scandal in this regard. But they sure do have a lot more equipment in the engine bay, and just maybe it's because they don't cheat and therefore need all that stuff to legitimately pass the tests? GM also, to the best of my knowledge, hasn't suffered that fate either. By now the EPA knows about Cummins and VW, so they're probably much more skeptical of ALL diesel certifications. I expect by now the EPA now employs IT/computer programming geeks to hunt down and find this stuff. Either Ford and GM are better at cheating, or just maybe they are better at engineering. Time will tell, but I've got to think the EPA is now actively probing all manner of cheating avenues. They've been fooled twice; they probably have a very sour outlook on being cheated again.
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I wonder where the $1.7B fines go? Does the EPA get all that money, or is it put into the general US treasury funds?