I am guessing this never happened before? When this happens, does the broil indicator on the display illuminate? Does the oven ever reach the preheat temperature? Your oven cycles both elements to preheat the oven, but the broil should not be on long enough to actually glow red if that is what you are seeing. I am guessing at this point you may have a bake element that has failed so now you are only noticing the heat from the broil element during preheat. Get back to me with any other details you can provide so I can get you going in the right direction.

OK I seem to be missing something. You say both elements will glow, the oven preheat times out and says it's ready, but it really isn't. And the broil element get hotter than when it is broiling. Does that about sum it up? What happens when you set the unit to broil? The control board (AP3851248) is the only component in your oven that turns the elements on and off based on the information provided by the temperature sensor. You are not getting any faults, so I would assume the temp probe is OK, and it doesn't control the element directly at all. And just to clarify, no work has been done on this unit? It sounds like the broil relay is stuck in the on position so when you start a bake cycle, it turns on and stays on instead of cycling. Because the temperature jumps up during preheat with the broil element always on, the bake element will cycle off and probably stays off because the temperature probe says it's hot enough. If that sounds like what it is doing, then the control is your failed component. If you are seeing other things, get back to me and I will see what else I can come up with.