Product review (5 stars): Replacing the control board did the trick!
My dryer would run fine for about 20 minutes then suddenly it would cut off, and pressing the power button did nothing I would have to wait 30 or 40 minutes before it would start again and run normally as if nothing had occurred. No error codes or any indication that something was wrong. I started with changing all of the thermal sensors. That didn't work, so I changed the motor thinking it was overheating somehow and that didn't work either. The problem continued to get worse with the dryer running for a shorter period of time and then taking hours before it would come back on. The last thing was the control board and eureka that did it and now I have a brand new LG dryer!