There you go. This is probably how it was done. Multiple maps with certain things triggering them. One map was "emission compliance", and came into play only in certain circumstances.

The way they did it wasn't all that technically clever. If the engine was operating without the steering wheel in use, which is the case during testing, the defeat device would direct the engine to maximize emissions. If the steering wheel was in use, the car turned off the defeat device so the engine would go back to its normal setting and maximize power and fuel economy at the cost of emissions. Emissions and efficiency are a direct trade off. Diesels run best when they are running dirty, so VW was able to score almost perfectly on emissions testing when the but then show great power, economy and efficiency in real life driving action.

I doubt EU NOX limits are 10-40X US limits. In which case they may well have cheated EU regs too. And the VW engines were used on other cars in the VW group, I think Seat and Audi.

Car companies are king in Germany. But not in other EU countries. And Germans are ardent environmentalists and they don't like rule breaking.

So now waitaminit.

I have a Scanguage II permanently mounted on my dash and plugged into the OBD port so I can monitor MPG's, etc. in real time.

Does this development mean that it could be possible that my truck engine is operating in a fake 'being-tested' mode? Will my engine perform differently if I unplugged the Scanguage?

That is not how it works....you are fine.

to help with translation from English to American, an MOT is an annual transport test cars are required to take for them to be legal on UK roads

http://forums.pelicanparts.com/uploa...1443264043.jpg

That's what this article is saying.

VW Could Fool the EPA, But It Couldn't Trick Chemistry

"The ICCT reported its findings to the EPA and the California Air Resources Board. Regulators met with VW officials in 2014 and the automaker agreed to fix the problem with a voluntary recall. But in July 2015, CARB did some follow up testing and again the cars failed—the scrubber technology was present, but off most of the time.

How this happened is pretty neat. Michigan’s Stefanopolou says computer sensors monitored the steering column. Under normal driving conditions, the column oscillates as the driver negotiates turns. But during emissions testing, the wheels of the car move, but the steering wheel doesn’t. That seems to have have been the signal for the “defeat device” to turn the catalytic scrubber up to full power, allowing the car to pass the test."

http://www.moreaboutadvertising.com/...kswagen_01.png

Over here (in Belgium), emissions are tested during annual technical inspection.
They just put the sensor in the tailpipe and rev it. How does the car know it is being tested?
How could it even pass todays emission standards when it is that much worse than claimed?
Makes me wonder about our tech inspections.....

Tailpipe tests for registration are gross checks, not nearly as strict as 'new car' regulations. And the allowable emissions increase as a car ages.

OBDII tests simply check that the monitors are functional, or most of them are. More monitors are allowed to fail as a car ages.

EPA / certification for sale tests are not the same as registration checks.

This. It's a total joke. My 993 is 1996, the first year of OBDII. When I first got it, VA was still doing the dyno/tailpipe/sniff test and the emissions were as clean as a bicycle. But geezus, have an issue with unreset readiness monitors and you're public enemy #1, can't pass emissions and it's a very difficult fix. The testing station doesn't care at all what's coming out of your tailpipe; they care that their computer can read your car's computer. That's it. It's sort of like going through airport security. As long as everyone has been screened, nothing can happen. Right? That's how the US does things - make everyone feel good, ignore real problems. And since we're probably VW's largest market, it's just easier to make all their cars US-compliant.

If simple tailpipe checks were effective and all encompassing then the EPA would test all cars that way.....look at the equipment UWV needed to test the diesel cars, there's a reason they didn't simply sniff the tailpipe.