The washing machine would allow you to program it, and all the lights on the control panel would light up, but pressing start did nothing. I tried putting the washer in diagnostic mode, but was unable to do so. The machine was not showing any fault code.
I originally thought it was a problem with the 'Start' button and I thought that I'd buy a replacement part from the original seller of the washer. I was told by the 'live help chat person' that the problem was likely in the washer user interface unit that lay behind the button in question, and they'd be happy to take $340 for the interface unit. I thought that perhaps eBay was a better answer for parts for a 15 year old washer, so I started to shop. As I waded through the eBay used parts, I noticed a comment that said, "hey, take a quick look at the door switch as that can cause similar problems." I looked and saw that the door closed detection pin that sticks through the door surround had been either sheared-off or pushed in to the point that it was inoperative.
I abandoned the search for a replacement washer user interface unit and just bought a door switch assembly. Even though I didn't have replacement parts, I did the disassembly right then so that I'd know whether the washer door boot spring clamp was rusty and also needed replacement. (Nothing worse than waiting for a second round of parts to arrive.) I followed the YouTube video from AppliancePartsPros to change the part. Once parts were in hand, the total repair time was only about 15 minutes.