only if the vehicle has the option. There is a thread in here somewhere regarding this option. Something about setting park brake and using cruise control to hold at a determined idle. You have to do it manually. I'm not sure if the auto-idle can be adjusted with EFIlive or not. I'm sure someone will chime in though.

My high idle progressively goes up to 1300 as the truck warms up so as not to rev too high when cold. then lowers to 700 as the truck hits a good temp.

But when my truck is plugged in over night, it'll high idle for about 3 min then lower down. If not plugged in it runs high for about 7-10 min. (sucks alot of fuel).

 

also, here's the write-up to do it yourself.

http://www.dieselplace.com/forum/showthread.php?t=298191&highlight=high+idle

 

My truck has the elevated idle option, it only kicks in when when the truck is cold, really cold, generally every day in January in Wisconsin. No voodoo to get it to work, it just idles up when needed and idles down when warm. As for parking brake, bad idea when it is that cold, any moisture and you could have a problem releasing the brakes if they freeze.

As for manually elevating the idle, only way I know is step on the accelerator

 

chevydmax04 is right on. I live in MN and deal with same temps. With the elevated idle activated, it works mostly on really cold days when the truck is generally left outside unplugged and it disengages when it warms to a specific temp. Once the truck has been started for the day it usually will not kick back on again unless its really frigid roughly 20F or lower and the truck has been shut off for a long time. Hope this helps! It really helps warm the truck but it really eats fuel too!

As far as activating it when wanted never heard of that before, and I would be real leery about setting the parking brake in cold temps. I had a family member do that one time on a 3500 hd at a boat launch in cold temps and they had to cut the parking brake free because it seized up due to the cold and moisture.