Theskate

Hello I’m new here and need so e guidance. I have a 2014 Ford fusion SE 1.5 L. My concern is my engine is overheating but no mechanic is able to find a reason. I have replace the radiators, the thermostat, flush the system and put new coolant in, and I’ve also replaced the coolant temperature sensor at the drain plug. just to confirm I did everything correctly I took the car to Ford and have it pressure tested and they found no pressure concerns. My car ran fine for almost 2 months in the hot summer in Arizona and now it has begun to overheat at high speed on the freeway. My warning lights come on I pull over shut down and let my car cool off. Does anyone have any idea My car is doing this? I’ve taken it to two other mechanics cents and they have no idea what can be causing this issue. There is no reading from the ECU indicating any faulty system errors. Also how do I reset the ECU?