2006 prius engine mystery

Hi all, I have a 2006 toyota prius with 266,000 miles on it. It has been having some weird issues. It will crank, the engine will run and charge the battery bank to about 5 bars and then the engine will cut off, then if I press the accelerator the engine will not run, when the batteries deplete back down the engine will run but when I put my foot on the gas the engine will not engage. Also when the engine does run there is an awful loud knocking noise coming from the engine at idle but when I give it gas the knocking sound disappears. This all happens in park. When I drive, it will eventually shut off and stop all together and not run at all. Any answers will be appreciated.

 

Can't make a video at the moment, the car has been parked and we have to take the battery out of our other car to put in the Prius so that's a thing.
The 12 volt battery had gone bad in the Prius so the Prius battery does not work. Do you think the 12 volt battery going bad could have something to do with it?

Sorry can't make a video of it right now, we have to take the battery out of our running car to put in it to power it up.
When we power on the car initially the engine will run until the battery charges to 5 bars and then it will shut off, when the battery depletes but the engine will not start up to charge them back up, even if we press the accelerator the engine will not start back up. The engine, when it is running, will knock loudly at idle but when you press the accelerator it will diminish a lot. This is all while sitting in park.
If we try to drive it , it will only go until the battery depletes and then it shuts off completely.
Lights in the dash lit up are: the check engine light, tsc light, abs light, and the big red triangle light.
Haven't had an opportunity to check for codes.
This car has been sitting for a couple of years because instead of spending a lot of money to try and fix it we just got a used Toyota Avalon at a good price instead. We were just trying to get an idea of what it might could be so we will know if it would be worth it to try to repair it. Thanks for your response!

 

The Pee Dee area

 

We have no way to read the codes. We do not have a code reader.

 

About 25 miles away in Dillon County

 

This was the problem we were having with the car before we parked it. Had not been having any problems with it then one day out of the blue it did all this. I really loved that car too!
We have read that it could be the 12v battery but we don't really have the expertise to work on a high voltage car lol

 

We had read that the problems that made us park it in the first place could have something to do with the 12v battery. I know it died shortly after parking it and would not charge back up. Our problem is that the battery that goes in it is about 250 dollars and we haven't been able to afford to buy one to test that theory out, plus if the battery is not the problem we cannot return it because of their store policy so we would just be out 250 if that wasn't the problem.