Prius warning light. Will not start.

Hello all. Newbie here. To start off, I bought this Prius about a year ago needing a new HV battery. It had been in a wreck, replaced the front bumper and painted it. Got the new battery in and everything was fine. I went out of town for work for about six months came back and drove it and everything was working OK. Two days ago I was driving home and the triangle of death warning light came on along with a check engine light. Soon after a fall at the brake light VCX light (I'm assuming, (but really I've been drinking)) along with the ABS light and the (!) Light. I replaced the 12 V battery and drove it home from O'Reilly's and about halfway down the road these lights come back on along with a solid warning sound. The AC quit working and I can hear a fan constantly running in the back even after I turn off the AC. After reading a couple of post on this forum, I checked the HV battery to see what caused the triangle of death light. All of the battery cells in the HV battery test to be 7.8 V. After cleaning the copper connectors on both buses(they were pretty corroded), I get everything plugged it back in and back together and now my Prius will not start. I have an off day tomorrow and I plan on using it to troubleshoot what the problem may be. Any help is appreciated. I'm desperate!

 

Well I say new battery, it is new to me but it was used.

 

I will also add then after putting my scan tool on it, the original check engine light code was for a coolant flow control valve, but after it would not start a new code came up for battery voltage being too high Or too low. I checked the onboard diagnostics and the HV battery looks OK and the 12 V battery is new.

 

I double checked every plug in and everything is in it's correct position

 

Also thank you so much for your quick response

 

You're talking about the big orange safety plug correct? Isn't it supposed to slide down? I even jiggled it back and forth to make sure the connection was certain.

 

The onboard diagnostics shows the 12 V battery actually being 13 V or something close to it I can't remember. I am about to YouTube the connection sequence now.

 

@fotomoto would that be caused by the coolant control valve? That's what the original code was for anyway. The safety plug is definitely in and making contact. As stated earlier all cells read 7.8 v or more.

 

@Osxarsam17
I will check that tomorrow morning as I am not around it at the time. I had to drive my turd Pontiac grand am home this evening.

 

Watching several videos tells me that the HV battery was plugged in with the correct sequence. Further help is well appreciated!!

 

Bump

 

@fotomoto can it be done without going into ready mode?

@bisco how can you test under load? I'm probably asking some dumb questions but this car is like learning a foreign language to me lol

 

The code I'm receiving is C1241 "low battery positive voltage or abnormally high battery positive voltage"