VW Group Diesel Scandal aka dieselgate

So I'm wondering if anyone else here has been caught up in this scandal? I've got a 2010 Golf TDI, that I'm just a few payments away from calling my own. I'm more that a little upset at all of this.

I'm also more than a little intrigued about how this all happened and the technical tricks they played seemingly not just on the EPA, but regulators in the EU as well.

For now I'm just waiting on what technical fix they come up with. I'm not that up on how exactly the emission control system effects the engine. I have heard some concerns that there may be increased stress caused by higher running temps, but really I haven't a clue. But I do feel I was sold "a bill of goods" and really hope they can make this right either through a fix that doesn't totally ruin the performance or durability of the car. Either that or some sort of buy back.

As to what the EPA and others do to the VW group, that should certainly be interesting.

There is a forum for that. They are a nice crowd - I used to own a 2000 Gold TDI and hang out there a lot.

VW is not going to do a buy back - what would they do with all the cars? They will update the firmware in the ECU to lower emissions. What impact this will have on the performance or durability is the question. There is also an issue of re-sale value being impacted.

Yeah, I've been perusing TDI Club and VWVortex. TDI Club has a little more rational discussion going on for the most part.

Curious as to what the folks here have to say, since we've covered just about everything else under the sun!

EDIT: As to a buy back, I to doubt they'd go that route unless they just couldn't meet the EPA standards without some really serious engine issues. What they'd do the cars? Scrap them and maybe gets some parts for the non-diesel cars to sell to third parties?

I have two vehicles from Chrysler that are listed as "buy backs." However to be eligible you must not have responded to any recalls. I think Chrysler is being punished for not notifying the customer of recalls, a different situation.

I would think performance would be impacted by any fix. If a fix was easily the VW staff would not have cooked up this "trick" and risked their jobs and the company's reputation. I would be reluctant to get the "fix." However it will probably be the most looked at car code ever created

I don't know much about the particular issue that the VW computers have, other than what the news articles are saying, but... based on what I know about:
- Cars
- Computer software
- Byzantine government regulations
- Reading between the lines in news articles...

I think that this VW thing is probably getting blown way out of proportion by the news. They seem to be singling out VW as some evil company who deliberately falsified emissions on the cars. I'm not sure it's that clear-cut. From what I could gather from the news articles, VW's chairman stepped up, apologized, and said they will work to fix it, which I think is good. But I'm not sure he even needed to go that far.

First of all, the news article I read made reference to other EPA test failures on other diesel vehicles, including commercial trucks. I'm assuming that the article meant commercial trucks from a variety of companies. I think that if there's a true environmental issue here, then that's likely where the largest part of the problem lies in terms of gross tonnage of greenhouse gases. My guess is that VW's passenger cars would be a relatively minor issue in comparison.

And if other companies had similar issues, if that's true, then VW need not be singled out. The news articles which single out VW are being disingenuous in that case. Maybe VW was just doing what everyone else in the auto industry is doing. Was what they did really that much worse than what other companies did?

Then there's the issues of the complexities of computer software, interacting with the complexities of government regulations, interacting with the complexities of diesel engine operation. I'm not entirely convinced that the engine management software was deliberately coded in a nefarious way. There's a lot of places for problems to crop up in that set of complex interactions. Even if VW's chairman stepped up and took the blame, I'm still not sure what went on behind the scenes. Maybe the coders were trying to follow regulations and misunderstood, or there was some kind of a bug, or there was a problem that was missed in quality assurance. Or, maybe, diesel engines emissions are difficult to control no matter how you slice it, and occasional problems like this are inevitable. The news articles seemed to imply that there was deliberate fraud going on without actually citing any solid evidence that this was done on purpose.

It's still a bad problem, and still needs to be fixed, no argument there. Global warming is a scary and serious problem, and things like this are among the reasons why.

I'm just a little skeptical about the news organizations regarding this particular story. I think they were excited about being able to point the global warming finger somewhere and ran with it a little too hard.

Once 3rd parties started publishing their findings, VW themselves did the right thing and admitted to this wrongdoing as part of their commitment to correcting it alongside authorities. Whistleblowers are emerging into the public space indicating these "deviations" were something the supplier Bosch had warned against dating back to 2007.

The CEO/Charman also stepped down over this.

The article you linked about Bosch is interesting. Again, reading between the lines on that article, it sounds like the problem is in Bosch's software, not VW's.

To me, it reads a lot like the old video card driver issue. You know, when you've got a bug in your ATI video card driver, and you run the ATI reference drivers instead of the computer manufacturer's drivers because the reference drivers fix a particular crashing bug. ATI always tells you to use the manufacturer drivers, but you've found that the reference drivers work better with fewer bugs, because they're newer. Sounds like VW was just shipping the Bosch reference drivers, as it were.

I'm still not yet convinced there was any deliberate programming effort to falsify emissions tests. I think the news articles are failing to grasp the complexity and the potential for bugs here.

Here's a readable and technically detailed article about how you build a proper, low-emissions 2.0 liter diesel engine.

The gist seems to be that the TDI's will drop somewhat in horsepower/torque and mileage, but not outrageously so, and aftermarket tuners will be happy to give all of that back to you if you don't care about your emissions.

The deeper thing to ponder is whether VW will have some sort of requirement to "just" repair your car to meet the specs or whether they will need to further compensate you for reducing the vehicle's value and/or give you some outrageously long powertrain warranty to cover any of the issues that apparently come with running a diesel engine "properly".

If I owned one of these cars and VW offered to fix it gratis, give it a long warranty, and cut me a $3000 check, I'd probably say "meh, good enough" and go on with life.

This is what both VW's internal investigation and the government side is focused on. VW's admission is indicating that the software change it's self was deliberate for a bench test setup for the engine, possibly instead of the engine being fully installed into a vehicle. My guess would be for tests without all the components that help with emissions downstream of the engine block.

The EPA side is pointing to this change possibly evolving into the defeating emissions testing aspect.



*edit* At this point the question of deliberate or accidental likely only changes the punishments VW may face. Either way, this is a pretty big issue that has resulted in a €6.5bn hit to VW's finances already, before any fines have been levied.

I think the Bosch bit clearly shows it's not an accidental outcome. At some level VW knew, and chose to bury. That's on VW.

Half a million in the US, another 10 million or so in Europe. It's messy. Paris seems concerned, anyway...

One report I saw (can't find link; sorry) suggests some car companies build engines that perform well under "lab" conditions, but when you floor it, they suck - and emit.

-jk

Again, reading between the lines:



That right there tells me that I can't trust the article on any of the technical details.

I don't believe there would have been an extra "device" attached to the cars. It would really surprise me if there was. I think that saying "defeat device" is due to a misunderstanding of the way engine management computers work in modern automobiles. If there was anything going wrong, I expect it would be in the software of the existing engine management computer, not in some kind of extra device attached. I think that somewhere, some expert who was talking about the software, mentioned something to a reporter about a theoretically-possible software routine that could defeat the tests, and what came out in the news articles is the end-result of a Telephone Game played by news reporters who don't understand software, and now it's a "defeat device".

Stating that the software could "sense test scenarios" based on those items such as air pressure and whatnot... That also misunderstands and misrepresents the technology. All engine management computers always monitor all of those things as a normal part of what they do. The news article is putting those sentences together and IMPLYING that those pieces of information were used to defeat the tests, without actually saying that anyone had proof that those pieces of information WERE used to defeat the tests. Again, it's a Telephone Game played by people who don't know how these things work. They're making an inference based on someone saying that those values are monitored by the computer and that they COULD be used to detect and defeat a test scenario.

The smoking gun proof will be: Someone looks at the actual software code and proves that the software deliberately detected a test scenario and then changed the engine output based on that. I haven't yet seen a news article solidly citing, from an expert source, that that occurred. So far, all I see is a lot of inference and innuendo which tries to imply that that's the case, without citing any actual detail there. Any place where someone tries to cite detail, it all looks like that Telephone Game problem. I'd like to see some better, more clear articles, which don't have that problem. I'd read those with great interest.

Of course, as you said, that will be discovered, or not, in the investigation. I'm just saying, I'm not going to damn VW until that happens. Until then, I believe there's a chance that their company president might have resigned over what actually amounts to a software bug. Of course, if that's the real answer, we won't see it in the main news cycle. That won't get reported on.

The other issue is the claim of Bosch telling VW not to use that software. Again, I don't know the details because the news articles are sketchy on it. That sketchiness is what makes me skeptical: If Bosch made the computer and wrote the software, regardless of whether or not they told VW not to use it, then why aren't they in the crosshairs here too? Why would Bosch write software that defeats EPA tests? I think there's some missing detail in the reports regarding that aspect, something that we're not hearing. This will also come out in the investigation, but likely not get reported upon either.

True, we'll need to wait until the actual code comes out and we can all see what it exactly did and did not do. But the fact that VW has all but admitted guilt here says volumes. They've now set up a site for owners to learn more. There isn't very much information on there right now however.

VW Diesel Information Page

Still, I'm concerned that the "fix" will end up depreciating the performance of the car to a point where it's not a fair equivalent to what I was told I was buying. Hopefully not, but we'll see!

What are the odds that these type of programed control units are opened up to the public to view? I'd think the automakers would be very opposed to that.

Aha, I found why the term "defeat device" is being used. This is a legal term that hasn't changed to match modern times, but has had it's definition updated.

Exactly, there isn't a separate device but the programming contained within the normal ECU or other such device that contained a separate programming routine that deviated from the stated purpose.

Maybe. Or maybe they are simply responding to those news articles and to the EPA, and, realizing that public opinion is everything, doing whatever makes them look as though they are trying to Do The Right Thing, i.e., apologize and clean up the problem whatever it turns out to be. This is the only way for a company to retain the respect of their customer base. I think that even if it turns out to be something other than a deliberate act, this was still the right thing to do at this stage. They're acknowledging that the EPA discovered a problem, and that they will do whatever it takes to fix it. This doesn't mean the company currently believes the problem was deliberate fraud on their part. It might, it might not. But I don't see them hanging themselves quite yet.



Aha! Very cool! Yes, that makes sense! And yep, it was a telephone game: The BBC article that was linked earlier, treated it as though it was actually a separate device, even calling it a "sophisticated piece of kit".

I understand enough about engines and computers to make me dangerous, but the byzantine nature of government nomenclature and regulations is completely beyond me. Though I understand how the regulations were probably written before there was a such thing as modifying the software in your car's engine management computer.

The actual real technical details of this are going to be fascinating, when they come out. I'm super interested in that. I'm hoping for an extensive Ars Technica write up on it.

No, it isn't. It is deliberate fraud on a massive scale, 11 million vehicles, putting out more than a million tons of nitrous oxide emissions each year. That is more NOx emission than all of the UK's NOx emissions from all sources: power plants, vehicles, industry, agriculture, etc.

Of course it was. One of VW's engineers, according to VW's own records, stated four years ago that the software they were using was illegal, as did Bosch. We're not talking about "Oh, gee, under certain conditions the car emits a bit more NOx than it should." We're talking about a vehicle whose emissions are forty times greater than allowed, except when being emissions tested at which time it miraculously reduces its emissions, at the expense of fuel economy, performance, and engine longevity. The engine management parameters are completely remapped whenever the car is connected for testing. That's not a slip where they programmed in ones and in zeroes and temporarily ran out of ones!

It is Bosch's software, but it is VW's problem. The software that VW used was provided by Bosch as an engine development tool and VW was explicitly told that it was not legal for road use. VW couldn't meet its economy, performance, and longevity goals with all the emissions controls in place, so they used the engine development software to enable the emissions controls only during emissions testing. They were told by their own engineer and by Bosch not to do that. They did it anyway.

Because the software worked properly for its intended purpose: Engine Development. It was not intended to be used on the road. VW knew this, and used it anyway.

How much proof do you need? Both the EPA and CARB (California Air Resources Board) have demonstrated conclusively that the emissions performance is totally different when connected to an emissions testing device, following the discovery of this unusual behavior by the team at West Virginia University. This could NOT happen serendipitously. [Hah! I claim first ever usage of that word on this bbs!] It would require some deliberate and pretty sophisticated coding to accomplish it.

VW has admitted it. At first they tried to whitewash it with a voluntary recall of the half million US cars, but CARB caught them with their pants down and they had to 'fess up to the "dual coding" in their computers because it was so obviously and demonstrably the case. Then they conceded that there might be a few other cars with similar problems scattered around the world... another ten and a half million of them.

This is not a little mistake. It is a deliberate fraudulent action that netted VW billions of dollars in unethical profits, and the ultimate victims will be the 11 million people who purchased these cars (loss of value and loss of performance/economy/longevity if or when the problem is solved) and the VW stockholders who have already seen the value of their stock drop by a third, with possibly more to come.

It easily ranks in the top 10 of the worst frauds in recent history.

tanstaafl.

My primary skepticism was because the news articles I read seemed to imply all of those things without actually giving much in the way of details. And they got a lot of the technical details wrong.

The thing that convinces me the most right now though, is the EPA FAQ page that Tom linked earlier. Until he linked it, I hadn't seen it. It specifically accuses the software of defeating the emissions tests (though it seems to stop just short of saying it was deliberate), and says that the vehicles on the road are emitting 40 times more pollution than the laws allow. Since the EPA has the most information about it, though not all of it is public, they are in a position to know the most about it right now, and therefore what they're saying carries weight, so I'm certainly on the side of believing it for now.

The poorly-researched and poorly-written news articles I saw sure made it look like a lot less than they were saying it was, though.

Does any place still do exhaust tests on cars that are new enough to have the on-board diagnostics (1997 I think)? I know when I get my car tested, they just plug it in and don't do any actual measurements from the exhaust (they do measure the leakage from the gas cap, though).

In that case, why not just have it detect when the car is connected and turn on the emissions management then? The air pressure is dependent on your height above sea level, and steering position is irrelevant if the car is rear wheel drive on a moving road.

I believe I'm correct in saying that VW/Audi don't make any rear wheel drive cars, just front wheel and 4x4.

From misc reports, it could have been as simple as detecting that the undriven wheels are not turning.

Okay, here's an interesting article that talks about other instances of EPA test failures other than Volkswagen. This one gives a little bit more detail about other EPA failures of commercial diesel trucks which I had seen mentioned in other articles.

http://jalopnik.com/how-the-epa-won-1-billion-from-diesel-cheaters-long-be-1732109485

It has an interesting pull quote. Admittedly, the pull quote is second-hand and from a libertarian journal, but just thinking about the point that it raises is interesting:



That quote, and the rest of the article, and the other articles it links, makes me wonder if this kind of "cheating" has been an industry-wide standard practice for a long time. Where do you draw the line between "making your engine pass the test" and "cheating to pass the test"? It's a hard question. We have our own personal opinions about where that line might lie, but perhaps the auto industry in general thinks of it differently. And maybe us laypersons don't have all the information about how these engine management computers work.

Though widespread cheating doesn't make it right to cheat, and this is still a major environmental issue no matter how you slice it, it does reinforce some of the points I was making in my first post in this thread, about VW getting unnecessarily singled out in the news reports. This is clearly a battle that's been going on between carmakers and the EPA for a long time.

In this case, "drawing the line" is rather simple: VW specifically added code to detect emissions testing, and alter performance of the engine during such tests.

That's way across the line.

Designing an engine that satisfies specific emissions tests is one thing, but having one detect such tests and change behaviour during them is another.

Agreed, that's way across the line, if that's what they did. The investigation will hopefully conclusively show that, one way or the other.

I may sound harsh, but if that did not carry with it issues for so many employees, I'd wish them to go bankrupt. What they did is insanely unethical. It is yesterday's news (I think), that this is extending to more 3 liters engines, quite popular in EU also.

I do hope they don't gat away with it easily.

I am particularly disappointed because I've owned VW for quite some years. My first car was a VW Polo, which I owned for 2 years flawlessly.

The stellar reputation VW had had for years here in EU, and my own direct experience, made me buy an Audi A3 in 2003 (pictures of it are on this board, my Empeg has been in it forever basically) almost out of blind trust in the brand, besides liking the model very much. I owned it until 2013. 10 years.

The list of issues I had with it is almost unreal. Engine head issue, AC issues, finishing and interiors material issues, xenon lights issues, and in particular a clutch issue that VW seemed unable to fix for two years and seven (7!!) visits at their official repair shops, more and continuous smaller issues here and there, and eventually a SECOND engine head issue (!!) made my fast and shiny A3 a real pain to own. Problems were, in my opinion, way too many to be ascribed to an "unlucky" unit. I think VW at some point started to give up on quality trying to leverage their incredibly good reputation (at least here).

This scandal seems to confirm my suspicion that some serious, deliberate poor management was happening. While it is hard/impossible to know what really happened inside the company, and I have no evidence of my own experience with my A3 is in anyway linked to Dieselgate, well, you know what, they're definitely not having me as a customer again in the foreseeable future.

Also because my next car will be a Tesla Model Y. I hope.

Thank you, Doug. I am surprised that VW is getting any slack on this. If I owned an implicated VW Group diesel, I would settle for nothing less than a complete buy back. The notion that VW can apply some sort of fix that would both lower emissions while meeting promised MPG/fuel economy numbers seems like a pipe dream. VW buyers were defrauded. I loved my GTI 16V but would never buy a VW product again.

Jim

I would like to amend that statement. WE are the ultimate victims.

tanstaafl.

Unfortunately, there's no such offence as "statistical corporate manslaughter".

If you abstractly treat a corporation as a large pile of money holding together a bunch of engineers and equipment, then a big fine is not unlike killing off a part of the corporation.

That causes the organism to grow scar tissue. Er, I mean that causes the organization to hire lawyers.

Scar tissue, or more muscle mass? (side tangent with a larger colony of organisms, and a more on topic key point from the tangent)

The only faith I have in the VW situation leading to legitimate scar tissue is the EU oversight on this too. US only, doubtful they'd be harmed much beyond a bruise.

http://hackaday.com/2015/12/31/32c3-dieselgate-inside-the-vws-ecu/

I found that video very interesting, it goes through the specific programming of the cheat function exposed through reverse engineering of the ECU. A really excellent talk, and worth a watch.

Thanks for posting this. When I get some free time, I will watch those talks so that I can understand the details better.

I find it interesting that the cover article repeats what that other libertarian article said:



I agree that gaming the tests is still wrong when you're talking about our planet's climate. But maybe the people who design the tests are also partially to blame here: The tests should not be so easy to game. I hope that this scandal has given them a wake up call, and has made them start working on improving the tests.

There are plenty of examples in other aspects of our legal system where people game the system. In most of those cases, we either applaud them for "sticking it to the man", or we shrug our shoulders. For instance, the way large corporations weasel out of paying taxes: When they follow the letter of the law and successfully get out of paying the taxes, we don't fine them for breaking the law, we complain at our lawmakers for having the loopholes in the tax code. Why are we treating the emissions tests differently?

Laws are often inconsistent and complicated, and as long as the lawbreakers still have an incentive to skirt the law and exploit loopholes, they will do so. There should be as many protections as possible to plug loopholes. We make prisons escape-proof because the inmates have an incentive to break out, so a lot of technology has gone into that. Since cheating on an emissions test is something serious (arguably more serious than an inmate breaking out of prison), then we should apply some technology in that direction too.

The video is awesome! They reversed hacked the code, and found it was programmed to detect the testing protocol, and if and only if it was met, the engine would run clean. Otherwise, it would run dirty.

Fabulous hacking! Lousy testing protocol...

-jk

I watched the video. It's really a smoking gun that this is absolutely a deliberate attempt to detect the testing cycle and produce the desired output just for the test. This is exactly the kind of detailed analysis of the code that I wanted to see.

It's also interesting how, in the video, they talk about how other car companies were caught doing the same thing, and that this kind of cheating is widespread. But the companies who did it in the past are not well-known for it in the way the VW is today. In the video, I think they said it was BMW in, I think they said 2000, who were caught doing this and they got caught and then fixed the problem, and then were smug about it when VW was caught in the crosshairs this year.

I think that my initial impression that VW was being unnecessarily singled out by the media is still true. But my suspicion that this might be something more subtle than obvious test-cheating is not true. This is obvious cheating, and it's super clear-cut in the code, according to the demonstration. But I really needed that technical analysis to be convinced, because I know that the media twists things a lot.

Fascinating.

I'm afraid I must disagree.

Other manufacturers tuned their systems to legitimately pass the tests. The fact that the tests did not replicate actual driving conditions was not their concern. Had those cars been driven on the road in a fashion similar to what the government specified for the tests, the cars would have met the government requirements and in actuality would not have been polluting.

Volkswagen, on the other hand, had Bosch program their ECUs with two separate programs, one that passed the tests (just like the other manufacturers) and a second one that pretty much turned off all emissions control in order to give better performance at the expense of vastly excessive emissions. And the fun part is that the first program could never run on the road unless the engine temperature were some impossible negative degrees K, but would always run when the car was being emission tested.

That's not taking advantage of a discrepancy between test criteria and real life. I don't even have the words to describe what it is. Blatant, dishonest, egregious lying and cheating at the expense of the public at large (and even more so at the car owners' expense) in the name of greed and corporate profits.

I am not a fan of this sort of behavior, but I am also concerned that overreaction will cause "the baby to be thrown out with the bathwater". I hope that the people responsible for the punishment of Volkswagen will moderate their desire for revenge. How many of the 600,000 innocent workers employed by Volkswagen will lose their jobs if Volkswagen is driven out of business? If Germany's economy goes down the tubes, how will that affect the world economy? Just because I drive a Honda doesn't mean that I'm exempt from the possible financial repercussions of this debacle.

tanstaafl.

VW statement about what they did and didn't know:
http://arstechnica.com/cars/2016/03/volk...issues-in-2014/

It's directly admitting that some VW engineers decided to make the code changes to pass US emissions tests in 2005.

In addition the article states they, VW, intend to resume talks with the EPA today. This seems like it's been dragging on forever at this point without any sort of resolution. I'd love to know the details of those negotiations!

US settlement: $10.2 billion

https://www.washingtonpost.com/news/the-...issions-scandal

"The German automaker will pay owners between $1,000 and $7,000 per vehicle in compensation and promised to fix the cars free of charge to keep them from spewing 40 times the legal limit of harmful nitrogen oxides, according to the AP. Of the $10.2 billion, about three-fourths would go to car owners, with the rest paying off government fines."


-jk

Too bad we can't pay the planet.

Does this seem to be a different kind of settlement?

It seems like more money is going to the consumers than to governments and lawyers.

Press event is Tuesday morning. I think we'll get a more clear picture then. I've seen numbers ranging from $5000 to $10000 for a buyback and the $1000 to $7000 for additional compensation. I'm really waiting to see what they offer and a time-line. Can I go to the dealer tomorrow? I doubt that, they are going to have to schedule this I'd think.

Maybe they should/could be forced to contribute to some sort of eco/green initiative to offset the cost of their increased emissions making them "carbon neutral" or similar?

The buyback tables can be found here:

https://www.ftc.gov/sites/default/files/pdf/att._1a_-_buyback_modification_table.pdf

There are separate tables for the mileage adjustments as well.

Overall I think a fair deal.

In addition to the buybacks (a fix program is to be released at a later date, if technically possible and agreed upon by regulators) there is a penalty of $4.7 billion by the EPA.



https://www.epa.gov/newsreleases/volkswa...s-and-deceiving

"Consumers who choose the buyback option will receive between $12,500 and $44,000, depending on their car’s model, year, mileage, and trim of the car,"

Whoa! Somebody is serious about this!

tanstaafl.

So, if you keep it and it never meets reg, are you going to be allowed to drive it?

Interesting question. If your car passes its yearly emissions test, is there any way they can detect if it was repaired or not?

More specifically:
- If you don't get it fixed, it passes the test because of the cheatcode.
- If you do get it fixed, then it passes the test honestly.

I don't know if there's a way for a local emissions-test station to be able to tell the difference. Is there something like a firmware version number that the OBDII connection reports? If so, they could probably check that.

I was wondering more what happens if you choose to keep the car and no repair ever enables it to pass smog.

California has provisions for cars that fail. They involve making multiple attempts to repair the car until a dollar limit is reached, then you have to go to a referee. And you are dealing with the DMV sloths the whole time, who will take your fees and not provide a tag until your car passes, or gets the exemption.

Yeah, I knew about those particular rules regarding a car that can never pass smog. I used to live in CA and they have pretty much the same rules in WA where live now. I'm sure these diesels are all under the same set of rules: If it doesn't pass smog, you can spend X dollars to try to make it pass, and if that doesn't fix it, you get a certificate which says "well at least we tried", which lets you keep driving it.

My point is: With these VW diesels, if you choose to keep the car and also choose to *not* get it repaired (ie, you don't take it in for the recall to get the cheatcode removed), then none of the above will ever apply.

The whole point of the cheatcode was to make them pass tests every time. I'm assuming that whatever EPA test they were originally cheating on is slightly more rigorous than whatever the corner smog station can dish out. So VW diesels which didn't go in for their "cheatcode-removal repair" will always pass the tests at the corner smog station.

The interesting question is, whether the corner smog station will care whether it's running the cheatcode or not, or if they even have any way of knowing.

Can VW tie the compensation to having gotten the repair done? Is VW required to share the repaired / non-repair list with EPA & state DMV/RMV, thus enabling them to black list un-repaired cars?

Probably not on both of the above. The second one probably has privacy issues, and first because anything that gives the impression of VW not handing over the cash promptly is likely to be frowned upon.

Yes, they will know by reading the obdII version number.

I figured there might be something like that in there.

My guess, then, is if you don't remove the cheatcode then it won't pass smog because they'll see your computer's version number as one of the bad ones, and reject it outright. And since VW intends to pay for the cheatcode removal process (ie it's a recall, not something you have to pay for), then you won't be able to use the "I paid X dollars" excuse, so you're not eligible for the exception. From that reasoning, I think that most VW owners have to either take advantage of the buyback or take it in for the recall repair.