VSS sends a speed signal to ECM. I sell pre-programmed arduino clones that spoof a 2hz signal (1mph) which you can send to ECM instead and get Auto-Stop at highway speeds. But if you're handy you can make one yourself.
This is the development thread:
http://ecomodder.com/forum/showthrea...ght-34014.html
This post is where I finally get it working:
http://ecomodder.com/forum/showthrea...tml#post519692
I still sell these, $18 shipped anywhere in USA.
That's my button on the shifter, but you can put yours wherever you like.
Anyway, you hold down the button, throw it into neutral, and you should get Auto-Stop. Once Auto-Stop happens you release the button. To get the engine going again put it into gear and the IMA will start the engine.
You MAY have to tap the brakes, or in my case I have a brake switch on my steering wheel which is useful in its own right as a full-regen switch for the IMA, you can press that instead of hitting the brake pedal if you have one of those.
Using this setup, as opposed to an injector kill, is preferable IMO because you don't get the 10-second no-lean-burn timer once you've got the engine going again, and you don't get the christmas tree lights on the dash. You also don't lose power steering while the engine is off, but if you're a true hypermiler then you might want to remove the EPS, so that one's really just a matter of preference.