The problem is that nobody wrote a specific defeat device. You have to understand, Bosch has one basic (extremely complex) piece of software that goes in pretty much every single engine controller. There are some specific functions that are developed at the request of specific customers, but the basics are always the same.

When this general piece of software is set up to control a new engine from an OEM, a multi-year process of calibration starts. The engine starts of failing the emissions tests drastically and over time the calibration engineers tweak tens of thousands of parameters to try to get the emissions to be legally compliant.

This is not an easy process and the calibration engineers have a target, they have to get the vehicle certified for a certain emission class, which in turn is determined by the FTP-75 driving cycle. The news keeps talking about "defeat devices" because the law says that they are not allowed, but reality is much messier. There is nobody sitting there thinking about how to make crazy obfuscated defeat devices, rather there are a bunch of people trying to figure out how to pass the extremely demanding emissions requirement tests without any defeat devices.