What's this IG-ON mode use for???

Your previous car did this, too. You could turn the key to the ignition on position without going all the way to engage the starter. So why shouldn't the Prius?

And on your previous car, all the warning lights come on when the ignition is on but the car isn't running. Same with the Prius.

Some electrical systems in the car are engaged only when the ignition is on. This was true of your previous car, and it's true of the Prius. Sometimes you might want those systems engaged without the car running--or, in the case of the Prius, without the car in the "Ready" state. You don't want the transmission to engage or the engine to run, so you don't "start" the car--but you need the ignition in the ON position nonetheless.

You probably never never needed that for yourself with your previous car, and you'll probably never need that with your Prius. But your service tech certainly will need that capability.

 

<div class='quotetop'>QUOTE(Audio @ Apr 1 2007, 11:30 AM) [snapback]415890[/snapback]</div>

To open a window without switching on the entire HV system, for instance. Some systems don't work in ACC mode as the previous poster noted. I found out yesterday that the power windows stop working after a minute or so on ACC.

 

<div class='quotetop'>QUOTE(Tideland Prius @ Apr 1 2007, 01:22 PM) [snapback]415986[/snapback]</div>

As spelled out in the 07 owner's manual on page 43, column 1.

I'm amazed at how many people here love the high tech but don't read the owner's manual to their high tech $25,000 toy.

 

<div class='quotetop'>QUOTE(adam1991 @ Apr 1 2007, 08:04 PM) [snapback]416013[/snapback]</div>

I did read the manual. A year ago. It's no fun to read. And too much information, reading it is one thing, remembering how many seconds between engine off and no more power windows (and deducing that this also applies to ACC /IG-ON) is too much to expect from anyone with a life outside their Prius.