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Germany Detects Emissions Cheat Software In Audi Models (reuters.com)
The German government has accused Audi of cheating emissions tests with its top-end models, marking the first time the company has been accused of such wrongdoing in its home country. Reuters reports: The German Transport Ministry said it has asked Volkswagen's (VOWG_p.DE) luxury division to recall around 24,000 A7 and A8 models built between 2009 and 2013, about half of which were sold in Germany. The affected Audi models with so-called Euro-5 emission standards emit about twice the legal limit of nitrogen oxides when the steering wheel is turned more than 15 degrees, the ministry said. It is also the first time that Audi's top-of-the-line A8 saloon has been implicated in emissions cheating. VW has said to date that the emissions-control software found in its rigged EA 189 diesel engine does not violate European law. The 80,000 3.0-liter vehicles affected by VW's emissions cheating scandal in the United States included Audi A6, A7 and Q7 models as well as Porsche and VW brand cars. The ministry said it has issued a June 12 deadline for Audi to come up with a comprehensive plan to refit the cars. Ingolstadt-based Audi issued a recall for the 24,000 affected models late on Thursday, some 14,000 of which are registered in Germany, and said software updates will start in July. It will continue to cooperate with Germany's KBA motor vehicle authority, Audi said.
When you are testing emissions, you are doing it on a dynamometer - a big rolling drum. The car isn't moving. Thus, there is no reason to steer, and so the steering wheel won't be past 15 degrees either left or right. It's a perfect way to tell if you are testing, or actually driving. When you are on a real road, you are likely to turn the wheel past 15 degrees within the first 15 seconds of motion - pulling out of a parking space, backing out of a driveway, etc.
This isn't a bug - there is no reason for the steering to inform the tuning if the engine whatsoever. This is a deliberate cheat device.
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Here's how the VW cheat worked, and how Audi's does as well (aren't they same company?).
Basically, when you start the engine, it goes into "test mode" or the low pollution mode. There are a bunch of triggers that would take it out of test mode and into "normal high performance" mode. These are triggers that are believed if they occur, the car is not under testing. One of them is steering wheel - during the emissions test, it's not done on a road, but on a dynomometer, There's no reason to turn the wheel while on the dyno so it's assumed if the wheel hasn't moved it's to stay in test mode.
For Audi, another reason is acoustic management - when a diesel starts up, it makes a heck of a racket. However, if you inject a bit more fuel at start up, it quiets down at the cost of emissions (it's why the VW code references "acoustic management"). Since Audis are considered higher end vehicles, being able to do a nice quiet start is a plus.
And that's really the essence of the cheat.
It doesn't switch back and forth between modes. It starts in their low-emissions mode and then switches to high-emissions mode once they detect that the wheel has turned more than 15 degrees. A car in normal driving conditions would thus trigger the high-emissions mode almost immediately, given that almost every drive begins with having to either get out of a parking space, turn onto a road, or change lanes to rejoin the flow of traffic. But a car that's just spinning its wheels in place so that it can be checked for emissions under controlled conditions? It'll never trigger high-emissions mode.
As for why they weren't smart enough to make it work like you thought? They couldn't. The low-emissions mode achieves its lower emissions by sacrificing performance. If they sacrificed performance every time they started going in a straight line, people would notice pretty quickly that something was up.