Rough idle and triple icons on start

I left the car in ACC for a few hours on Sunday and drained the 12v battery.

Had a friend jump me off and said friend hooked the jumper cables up backwards on his car (stupid + sign water caps). It blew the fusible link.

FF to today I get the new fusible link installed, hook the jumpers up the right way, and the car starts right up. A few seconds after startup I get the big red triangle and three icons on the display, battery symbol, car with ! in the middle, and another battery symbol that says "MAIN" underneath. At the same time the engine idle became very rough and jerky.

I found another thread here about these symptoms after a battery swap cause by the ECU switching to defaults and the fix there was to power the car on and immediately shift to neutral and let it idle for awhile. I tried that for like 10 minutes twice and nothing has changed.

If I power it on and put it in reverse, I can back up normally. If i switch to drive, the gas pedal doesn't respond at all and I just creep forward very slowly from idling.

Any suggestions for a home remedy for this, or if dealer service is required, how much I might expect to pay?

edit: Pulled codes:
P0A80 Replace Hybrid Battery Pack
P2118 Throttle Actuator Control Motor Current Range/Performance

 

Woops I need to update my location on here. I'm in Lafayette, LA now.

 

bout 3.5 hours for a car that doesn't drive, yeah

 

I pulled the codes and I've got these two coming:

P0A80 Replace Hybrid Battery Pack
P2118 Throttle Actuator Control Motor Current Range/Performance

 

I don't have a multimeter and the thing doesn't want to go into diagnostic mode. It seems like the computer is rebooting or something, when I press and hold info the screen goes black before I've done the headlight flipping and then back to the prius boot screen..

 

The 12v in the trunk? I replaced it myself about...2009

 

So I connected jumpers again and left my Prius off while my jumper car ran for like 10 minutes. After that I was able to get into diag and it was showing right at 12.0v/11.9v when I first looked at it. Over a few minutes it gradually dropped to 11.6v while I explored the diag menus.

When I start my engine it jumps to 13.9v and the engine sounds good, then after a few seconds it drops down to 11.5v and at the same time the engine starts sputtering and trying to die on me.

Going to autozone to return their code reader and test the battery in a bit...

 

Well that's embarassing. 10a ETCS fuse causing the engine to misbehave. Replaced that and the car is running fine, but still have the error codes and autozone says the battery is bad, although good enough to start the car and drive around without any perceivable problems. Now to find someone to sell me a Prius battery that's not $225 Optima

Thanks for all the help everyone. To anyone who stumbles in with a similar problem, always check all the fuses and not just the fusible link when you reverse jumper cables!