Throttle body leaking coolant

Check the condition of the hoses connected to the throttle body first.

 

You can bypass the TB connections with a small barbed splice fitting as a work around, if indeed the TB is leaking. That will be OK until it gets cold.

 

Did I read that right?
$1200 for a throttle body??!!


First, tell your dealership that they're morons. You do not have to buy a whole new motor just to get a throttle body. When they ask you what the heck you're talking about, tell them that you were giving them the benefit of the doubt.....since it's better to be thought as incompetent than as an out and out thief.

Second. Verify that it's really the TB and not a hose.
If it really is the TB, bypass as mentioned above. If the leak is minor, then you can probably live with it if it's very slight while you source the replacement throttle body. If you're having to top off your coolant, then it's not a slight leak, and you need to start worrying about where your coolant is leaking to rather than from.

Thoid. Source a replacement TB. If you're REALLY not comfortable replacing this unit yourself, get an independent shop that you can trust more than your local dealership (which appears to be any or all of them) and get this done.
I've removed TB's for cleaning, and I'm not nobody's idea of a mechanic. It's wasn't hard, but I've never swung wrenches on a G2 before. I cannot believe that there isn't an instructional video out there for this procedure, and I'd almost be willing to bet that all you need is a 10-mm socket wrench, a pair of pliers, and maybe a #2 Phillips.
You can buy an entire motor on eBay for less than $1200!!

Forth. If you've a mind to help the Toyota community or you just want to vent, send an angry letter or fax to whatever Toyota has for a customer-care front here in N.A.
$1200 for a TB replacement is beyond crazy. Ask them what they pay their dealers to do this repair under warranty. Tell them that, of course, it's a rhetorical question but remind them that these nut-jobs are representing THEIR flag here in North America.
Just Sayin!

Reason #236 for the fact that although I'm a current Toyota driver, I'm a former Toyota owner.

 

Prius throttle body | eBay

You want one for 2004 to 2009

 

And if that is not the problem, you can buy a used throttle body w/motor for ~$100 as Jimbo pointed out, and replace that yourself as well. You'll need a new gasket.

If you buy a new throttle body it will come with the motor. MSRP is $914, discounted price of $685 here:
2008 Toyota Prius Parts - AutoNation Toyota Gulf Freeway Parts

The dealer quote of $1,200 is a bit high. Considering the part price is $914, it looks like they are charging you for 2 or 3 labor hours.

 

A gasket is not really needed unless the old one is destroyed.

I have removed the TB for cleaning several times. Never a problem with the gasket.

But it is cheap anyhow.

 

Prius throttlebody gasket | eBay

this may not be cheaper than the dealer, but by this point, you have to be leery of the dealer.