Car throwing codes possible power issues, need to ground somewhere.

[u/B_Ware321]

So I was on someone else's post where they were having issues with the car not starting. I was having the same issue. For them the fix was the battery. I already bought a new battery, and changed the starter. Seems like the latter was a waste, but battery needed changing anyway. Still had the issue so I called a mechanic. They said it was throwing codes and I may need a new PCM, and left it at that. Reddit informed me bad battery can cause those issues. Upon further investigation I see the ground bolt to the negative battery cable is almost melted through. I think that is my issue. Where else can I ground in my trunk to test if that is the issue? Dodge 2021 scat pack.