I have been chasing overheating issues for a while, to save face I won’t say how long. I have a 2014 Sonic 1.4L turbo. I have recently found my gremlin. If you are having mysterious overheating issues Check the three silver studs in your fuse box are tight. My right stud was loose enough to cause intermittent connection issues in my fuse box which misled a lot of my diagnostics by checking certain components off the list because when the car was parked it was receiving sufficient connection. Snug the studs and see if that fixes the issue. Good luck