My dishwasher has recently developed an issue where it will not complete a cycle. When it starts up, "add a dish" will show up on the front display (it's never done this before) otherwise, it starts up just fine. But after some time, it will stop, the "washing" display will blink on and off, and it pretty much just stalls out there. I honestly don't know how long it runs before this happens, since I haven't watched it while it's running.
After some digging, online, I found a way to run a diagnostic check, by pressing a series of three buttons , three times (123,123,123,) and close the door. In the video I watched (which showed a machine identical to mine)it said it should take about twenty four minutes for the full diagnostic check to run.
When I do this, every light illuminates (just like in the video), but when I shut the door, all the lights go out except for
"1 hour wash", "high temp" and "start" (in the video, all lights remained illuminated after closing the door), and the top display shows the codes"F6E4, "F9E4", "F5E1", and "F6E6",showing up one at a time, about 90 seconds apart.
And about 90 seconds after the last code pops up, the High temp light flashes two or three times, then all the lights flash once then everything goes blank, as if it were powered off.

Now, I'm pretty well capable of replacing any part that may be bad, but I don't want to buy something I don't need, so I'd like to narrow down the possible culprits before proceeding.
Thanks in advance for any advice that may help me remedy this problem!