Hi, I have a 2018 Kia soul 1.6 L GDI engine. It has 87,700K miles.  I have a code P0507 that keeps running causing my engine light to come on. A month ago My alternator get replaced because it said it was charging on and off. Local shop tested it bad many times. Replace it and the serpentine belt. Not long after my car started to idle high and rough. I took it to the shop and they said the throttle body just needed to be relearned. This fixed some of it but at cold start it revd a lot higher than usual. 18 days later the engine light came back on with the same code. And doing a regular check it says mt charging system is not getting proper voltage. I have inspected as many lines and i could to check for cracks also incase of a vacuum leak. 

Recent work done is 

-Oil and filter change

- engine air filter changed

-MAP sensor replaced

- Throttle body relearned. 

I dont know what to think at this point. Any advice I would appreciate it.