Online Demo / Manual- SFD
SFD (or "Schutz Fahrzeug Diagnose") Functions
So far in the US only the ID.4 and GTI/GolfR have this (also the A3/S3 at Audi dealers) but if you look in the AutoScan you will see some modules that say SFD at the end of the VCID. This means that module has some stuff in that is locked down and can't be changed without talking to the VW mothership. Using the factory ODIS scan tool online this happens kinda seamlessly with the user not really seeing that the module gets unlocked, just the Coding or Adaptation or whatever goes through. Some aftermarket scan tools claim to be able to get around SFD but for now VCDS can only do it if you get the token elsewhere. Humble Mechanic did a pretty decent job in a recent video on the subject.
There's a mechanism for ODIS users to do offline SFD as well, where the car generates a challenge that the user sends to the mothership later, and gets back an unlock response. Different countries seem to be handling this in different ways, and VCDS does have the ability to show the challenge string and if the user has a release token from ODIS (or wherever) then VCDS can use it as shown in the animation at the top of this page.
Keep in mind that even if a module has SFD that doesn't mean it has SFD for everything. For example, I was able to reset my service reminders (prematurely, just to test) using VCDS in the normal way that changes Adaptation Channels in the cluster without issue. In fact, the latest VCDS just works, click on the SRI Reset button, choose either the 1st (oil service) or 2nd (major service), click on Perform SRI, and voila, it works. I then tried to change an Adaptation channel in the cluster to show refueling quantity and the module was like , nope, sorry, SFD bro. Some modules have no SFD at all, and those act just like older cars for Coding/Adaptation/etc.
Important: Ross-Tech does not have any way of obtaining the SFD release token.