Lit up dash, doesn't turn over. Won't move.

sounds like you're back tosquare one. did you check the ecu connections?

 

Good news in terms of actual battery health... Take the covers off the battery ecu and see what's going on inside there? As in confirm all circuits are functioning. In meantime... You can relatively safely drive car around while clearing this particular code as you drive. But best to fix asap. This part that costs less than $100 may be needed:

 

Can you post some screenshots of what Dr. Prius app is seeing?

 

In meantime confirm all 14 voltage sensing wires are able to send a current, aka continuity test 'em.

 

Ok, then maybe check battery pack voltage... If your hybrid pack was running low before the snows hit and then you didn't drive for a week or two the voltage on the battery sides of the relays might be less than 200 volts... If that's the issue, the only problem is the need to charge and balance battery pack with a 250v 1/3amp charger.

 

Here's buyer's guide: Hybrid battery diagnostic and repair tool for Toyota and Lexus

 

First, get your multi-tester and set it to high voltage and plug in your orange safety plug and get a voltage reading on pack to decide if that's even a concern/cause of the breakdown. Then if it is:

Easiest way to charge would be if you get your engine running to put car in drive with foot on the brake and other foot flooring the accelerator. This is called a forced charge... Another way to do it is buy a hobby charger for NiMH and charge up each of the 28 8volt modules with a product like this: SkyRC Technology Co.,Ltd.

Or my friends and I created this thread: Build Hybrid Battery Maintenance Gear For Under $100 | PriusChat

 

Grounding out the 12 volts? What does that mean?

you sound pretty lost. There’s thousands of posts about hybrid battery repair
On this site use the search forums link up top and search

hybrid battery.

1—- All 12 volt battery measurements should be done from the jump point under the hood that’s the only place that voltage level means anything.
pretty obvious 12 volt is bad but measure that jump point with car off.
Then with car still OFF turn on the cars headlights in high beam and while there on measure the front jump point again. What are those 2 voltages?

Then pull the orange safety plug on the hybrid battery and r3move all the connectors on the ecu. Then remove that ecu can. It’s the slim box can about 9 inches long. It’s shown in the second YouTube you posted.it has the sticker on it.
Look closely in its plug sockets for corroded pins. Then take its cover off look closely on the backside of the plug sockets for corrosion. Hundreds of posts about this onthe SEARCH FORUM LINK.

If no rot you prob have bad battery modules which is just about the most common thing ever on this site. Start reading posts. Easy to test.