Ok, I have had this Maytag washer since fall 2011: # MVWC300XW0. It's only been used lightly at maybe 6-10 loads per month is all (bachelor). For some reason Best Buy at the time had it pretty cheap at $365, quite a bit discounted off its regular price of $500. Then I got a $100 rebate from the energy company since it's an HE machine. So, I have $285 or so into it is all with tax.
I had gotten used to its quirks, mainly it's had an inconsistent wash time that can finish in as "little" as 60 minutes or as long as 75-80 and even nearly 90 minutes on rarer occasions.
So after 2 years and 9 mos. of "trouble-free" operation (other than the occasional unbalanced load-it's been very sensitive about how the load is balanced), what's been happening now is that it won't finish the spin cycle and it just cuts power to the drive motor and at the same time the spin light & door lock lights begin flashing. After a few minutes the lock light stops flashing and just the spin light stays on solid. So I've had to cycle stop it and then switch the controller over to drain and spin for it to finish. But even now lately that doesn't seem to work well.
So I accessed the tech's service guide manual taped to the inside of the front cabinet. I verified that the green LED was lit up on the processor. I then went through the sequence to pull the processor's codes and found it has 3 codes: 1) main control fault, 2) a basket unknown speed fault, 3) as well as some kind of key code fault? I then went through all the "manual" checks that tests all the machine's functions as well as a tachometer test of the basket. Seemed to all function fine. I also pushed-in and wiggled all the electrical connections I could find on the machine. Once I get time I plan on doing the electrical checks relating to those codes since it's still apart. If nothing comes up with those checks, I wonder if replacing the main controller (not cheap) would be the fix since one of the trouble codes points to it...or maybe I should simply bail on this machine since it may become a repeat offender at breaking down? :(

Well another update, with only a 2 day wait on the part, I got the new optical speed sensor/shift actuator assembly installed today. I did some preliminary testing on its optical speed sensor to see if there were any changes in volt readings vs. the old one. Needless to say, I got an even lower reading of 1.81V (vs. the old one's 2.15V) with the new unit installed and plugged in to the main control. The manual calls for a 13V reading! So, I was beginning to wonder either I got a faulty new unit, there's something wrong with the main control's power supply circuit for that sensor, or the simply that the manual's test procedure calling for a 13V reading with the optical speed sensor plugged into the main control is incorrect. After checking that, I cleared all the trouble codes & then had the machine calibrate itself before then starting it.
Before starting it though, I wanted to observe the wash load in the machine as it was running. The only way I could do this was to remove the door lock latch off the door and plug it into the door lock unattached to the door. I held it in place with tape so it wouldn't move around in the lock either. This would allow me to lift the door at any time, or to prop it open to look at it continuously.
I ran two loads of wash thru it-with the first load a fairly medium size, and the second load a heavy, more typical, load. The machine did fine with both loads, finishing in at ~70 mins. for both. Everything went smoothly as far as I could tell. I then afterwards checked for trouble codes and there were none. So, perhaps other than replacing with a known good one, there is no real accurate way of testing a for failing (ie not completely dead) optical speed sensor?
Hope my experience helps someone out...