Urgent Help! Battery issues

I just replaced the 12v in my 2012 Prius C two. I started the car fine afterwards three times. I was able to take the car to Autozone to make sure the old 12 v was the issue and it was. I get home. Put all plastic covers back in place and now I tried to start the car again and it’s giving merge “check the hybrid system” warning. What the hell did I do? I really don’t see how there can be something wrong with the hybrid system when the battery seems to have had no issues keeping a charge and my gas mileage has been fine. The total miles for my car is 137316. And that seems too soon for the hybrid battery to kick the bucket.

 

So. I knocked the battery release. I put it back into it’s up position. The car starts again but still has the warning up.

 

Unhook the hybrid battery or 12v?

 

I don’t know much about cars so excuse my ignorance but do you have to charge a brand new battery? And how do you do that?

 

Yeah I had to buy from a Toyota dealership so I’d like to think they wouldn’t give me one not charged. And like I said the car started three times with no issue until I knocked the hybrid battery release.

 

I apologize for showing off my laziness but would I need to unhook both positive and negative cables or can I just unhook the negative for 10 seconds and get the same result?

 

I unhooked the negative for ten seconds. That seems to have solved it. Fingers crossed that I don’t see anymore issues. Thank you for the help everybody!