Trying to diagnose overheated engine with error code P1229

I have a 2006 Ford F150 V6 4.2L that overheated on the highway today. The gauge went to hot and it lost power. I pulled over and there was plenty of fluid, no leaks. The radiator hose was a little hot but I'm not sure if that's normal. Went to an auto parts store and read a P1229 Code from the computer. The fan belt squealed once yesterday and today for about 5 seconds when starting for the first time each day.

I thought maybe it was the water pump but it's not leaking. When I turn the car off after overheating and turn back on, the gauge goes back to normal. The check engine light stays on. Belt doesn't seem worn or cracked. The gauge goes back to normal if I shut off and restart car. No loss of fluid.