Originally Posted By: tfabris
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.

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.

Originally Posted By: BBC
the EPA has said that the engines had computer software that could sense test scenarios by monitoring speed, engine operation, air pressure and even the position of the steering wheel.

When the cars were operating under controlled laboratory conditions - which typically involved putting them on a stationary test rig - the device appears to have put the vehicle into a sort of safety mode in which the engine ran below normal power and performance. Once on the road, the engines switched from this test mode.


*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.