I spent months researching this and looking all over the internet...and the answer is that you won't be able to get any VSS signal from your X. Its far too computerized now and forces the installation of a "Speed Pulse Generator" (i.e., artificial speed sensor you install as a kit) to use this input. My Pioneer had the same issue but I have been using it without one for months now as it functions fine without (it uses the satellite signal and an internal gyroscope to determine movement, direction, speed, etc...) In an ideal world it would be easy, but on these rigs it just isn't anymore...