I googled for ya...dunno if the site is reliable, but here's what I found.

In 1992 Range Rover introduced electronic traction control. (that's what they said)

(here's what I say) I know that the Rangie, Disco, and Freeloader have traction control. I would assume that ETC came first and then somebody had the bright idea to make the HDC (hill descent control). I know that the Freeloaders and newer Discos have HDC. I haven't really payed attention to it while I'm cruising around the lot with everyone's truck, but I know people come in all the time whining, "My HDC, TC, and (oh, i forget the other one) lights are on."

I hope that helps a little. <img src="/forums/images/graemlins/patriot.gif" alt="" /> Good luck!