Bringing a Prius back from 4+ years parked

Hello guys!

I have been reading a lot on here and everyone seems very helpful! First off let me say I am new to Prius’s but am very good with cars. I got a Prius that’s been sitting for 4 plus years. I have no idea the condition of it as I took it in on a trade for something else (didn’t invest more than $200 on the trade). It’s a 2005 that was last driven in 2018 or 2019. It’s got a completely dead dash currently. The power button flashes red and the check engine light comes on. I have never got anything to come on the dash. The door locks aren’t working and neither are the headlights but the wipers and turning signals work.

Things I have done-
Replaced 12v battery with new one. The old one was dated from 2015 so I just bought a brand new one. It’s installed.
Replaced the fuse block under the hood- might be called the fusable link. The one with the clear cover. It was blown so I had to replace the block. It is currently getting 12.6 to the jump point under the hood.
Replaced the battery in the key fob- there is 3 key fobs for some reason in the car so I replaced them all. I have also messed with the key button under the steering wheel.
Replaced the hybrid battery with a known good battery. After I did that I got the car to start one time but the dash was still dead and nothing else worked. I tried to put the car in gear but it wouldn’t go anywhere. Left it started for about 20 minutes then turned it off. Tried to start it again in about an hour but the power button only flashes red and it won’t start any more.
I also checked all the fuses in the cab under the steering wheel. In the engine compartment fuse block I have checked all but the lower fuses as I ran out of daylight. Let me know if you guys have any ideas! Tomorrow after work I’ll finish checking the fuses and make sure I still have 12.6 to the fuse box. I’m also going to double check the AM2 fuse.

 

Also, tomorrow I’ll try and scan the code. I couldn’t get it to read it when the light was flashing red.

 

Update: had a couple minutes before I went to work. Still no start. AM2 fuse is not blown. But I checked 12 v battery voltage and it’s at 11.8. I’ll charge it when I get home and try again

 

Went to exchange the 12v battery today and they had to order one. It will be here tomorrow though. I have an obd2 tester so I’ll do a hybrid battery test when I can but the problem is my scanner won’t connect to the car since I can’t get it to turn on. Hopefully the battery fixes that and I’ll check all fuses tomorrow along with replacing the AM2

 

Also I'm wondering if this needs to be in the care and maintenance/ troubleshooting section. Does a mod have to move it there for me?

 

If you could move it for me that would be great. Thank you.

Update: put the new battery in. Still flashing red when I try and start it and dead dash. Checked the rest of the fuses and I had 2 blown ones. ETCS and Dome. Replaced them both and I’m glad to have the dome lights back. Maybe the ETCS is the reason I couldn’t drive it when I did have it started but I can’t even get that far now. I’m thinking maybe it is the combination meter. Is there any work around to that? Can I pull a fuse or anything like that to give it a try and see if that is it?

 

Update:
HV battery voltage at 212
12 v battery at 12.6

 

I put the back of it back together after changing out the 12 v and hv battery. I’m going to start working on tearing into the dash this weekend to get the combination meter fixed. The more I read on it the more it seems like that’s my problem

 

No luck with scanning codes. I can’t get the Prius to go into standby mode or start so my scanner won’t pull the codes. I have the dash all apart and the combo meter out but I’m beginning to wonder if that’s the problem. With the combo meter out and the push to start and key fob thing plugged in it still does the same thing- flashes red and I can hear a relay click on and off. That’s it

 

Any thoughts? This thing is stumping me. I think I may send the combo meter in anyways since I’m this far into the dash and already have it out.

 

Is there a guide on how to build a grid charger? Thanks.

 

Not getting any relay clicks after holding power button. If I need to, I’ll build a grid charger. But it seems like 212 should be more than enough to start the car on the high voltage battery. I have found online people being able to start their car all the way down to the low 170s. Also my 12 V battery is brand new and it’s got 12.6 V. Also should be enough if the key unlocks the car with the electronic locks it should be the right key correct? There wouldn’t be a case where the key unlocks the car but doesn’t start the vehicle right?