Possibly it's just that - I don't know the reasons/ways they are doing it.


If there is no/very little steering input, then I guess they could assume that the car is being tested (obviously comes into question what happens when you're on the motorway for instance, is this where ABS sensors come in?)


I wouldn't be surprised if they were set with a codeword and only for test vehicles... But I think (this is only my opinion) this would be a bit risky and would have been discovered a lot earlier.

Besides, with the coming investigations I'm sure all will be revealed!

Codeword - third party discovered this on cars in market, not 'test vehicles'. That's the way I read article linked in page 2.

Dyno tuning using high load runs could fall outside of emission testing procedures, thus never triggering this test mode. I've never had my car ran at WOT for emission testing.  So, it is possible this does not affect dyno tuning enough to be obvious.

Not that the article discloses everything, but it only mentions cat injection functions post engine. How does that affect performance?

There is a lot of bullshit written in the media. Best is to read the EPA letters to VW
http://www.arb.ca.gov/newsrel/in_use_compliance_letter.htm
http://www3.epa.gov/otaq/cert/documents/vw-nov-caa-09-18-15.pdf

It's pretty clear what is done:
-Reduce/turn off the regeneration of the NOx cat for better fuel consumtion
-Reduce/turn off AdBlue injection to reduce fill up cycles

Every modern vehicle has a "test mode" that is needed to turn of ESP s.o. when on the dyno. This is a normal procedure even when the certification test is done. So the ECU knows when it's on the dyno. There are a million other ways to detect the cyle as it has precise temperature/time/speed/gear specifications.
Every manifacturer optimizes the calibration for the emission test. There is nothing wrong with it. Typical engineering target is 50% of the emission limits on a new vehicle to have headroom with a aged cat. In the US you have to ensure that the vehicle complies to the limits even with a 150000mile old cat. Every action that reduces the effectiveness of the emission control system (enrichment for component protection for example) has to be explained to the EPA otherwise you won't get a certification.
Everybody in the industry knows how strict the US authorities are and what can happen if they find out that you cheated so it's a unbelievable stupidity that was done here.
Winterkorn is gone. The press wrote today that Audis head of development Dr. Hackenberg, the head of development from Porsche Mr Hatz, and the current head of development from VW Dr Neußer will follow tomorrow.
In my opinion they deserve it because all indicators tell me that they took that risk just to safe a few pennies for better hardware. 

And a 4th, given what Rick said

-Reduce power (alter injection time, lower boost) on the dyno so the car also runs much leaner (less soot) and combustion temps are lower (less NOx)

Someone post up a TDI flash. I have next to no clue when it comes to disassembly, but I'm looking to learn for sure.

I like how over this entire media phenomenon, no one has bothered to point out that vw likely saved over 2 billion gallons of diesel fuel, not to mention a "dirty" TDI is a magnitude of hundreds under NOx emissions limits for a similar output 2015 "heavy duty" engine in the United States (weight/power*time based output limits vs weight/distance so I used 35 mi/hr average speed to hopefully make this a somewhat valid comparison). Don't get me wrong it was a terrible stunt to pull, but if the EPA were serious about limiting NOx content, things would be a little different for commercial diesels.

My guess is that the current diesel car limits were set more based on lobbying from domestic car companies that didn't want to have to compete with German diesels and not based on scientific data.

My thoughts exactly. I'm inclined to think that this whole charade is because domestic manufacturers in US were being overrun by modern European diesel cars.

Anybody have an affected bin and an xdf or kp to go with it? I'd like to take a look.

http://nefariousmotorsports.com/forum/index.php?topic=9017.0title=

2007 MK5 GOLF GTI 2.0T FSI 6SP 1K0907115H

Is this one of them?