Code p3030. Battery voltage detective line snapped

I recently bought a 2002 Prius to fix up and sell not knowing how difficult it would be. It need cats and a grind battery. Got the cats installed fine. Then when I replaced the hybrid battery with another used one that was said to be in good condition. I got a p3191 code. I fixed that by cleaning the maf and throttle body. Now a p3030 code is coming up. I took the bud bars off and cleaned them. I didn’t see any cracks or major damage just corrosion. But the code is still there. The only thing I could think of being the problem is when I installed the hv. The wiring harness ( near where the hv battery vent and 12v battery sit) was crushed. It is the smaller plugs out of the 2 white ones. It’s the plug with 6 wires. I found the same plug I needed from a pick n pull and put those together with some butt connectors. I think I did it right, but I’m really not sure if that could be the problem or not. The code information says “battery voltage detective line snapped. Somebody please help.