Hello everyone, I'm new here. I'm posting this to hopefully help someone else who may have this issue.
I received an 05 Stratus for free from a friend. I needed a commuter car that I didn't really care about and was good on gas, so my friend offered me her Stratus that she was about to send to the junkyard.

It had a bunch of issues, mainly a charging issue where it would start and run no problem, but I was getting 12v at the alternator instead of 14.5 or above. There was also a check engine light, codes were mostly o2 sensor heater circuit codes, and a transmission control module code.
I replaced the battery and alternator and still had the same issue. I replaced the PCM/ECU hoping it was a faulty voltage regulator (its built into the computer on these models) but still had the same problem. I was about to give up until I looked further into the engine bay and wiring harness. I found a ground lug located under the master cylinder with 9 wires going to it, this is "G103" found on the wiring diagrams. It was so corroded there was no copper left on any of the wires and it literally crumbled in my hand when I went to loosen the bolt. I split the 9 wires into two separate bundles and soldered them to two new lugs.
This ended up fixing the charging issue and I'm now reading 14.5V at the battery terminals with the engine running. The check engine light and codes have gone away as well.

So if you're having this same issue, check your grounds first! I would've saved some money if I did this before ordering a new ECU.