A bit old but I followed this thread with my WDF540PADM 3 with the same sympotms but found it was too different for these steps to apply - it was less than 2 years old at failure. What I did find was the code sheet saying to press the 1-2-3 buttons three times in succession, which did not mean much when you don't have numbered buttons. What they meant was the three selection buttons from the middle to the right side in succession and it flashes the code on the blue LED. It gave me a 4 3 code stating the motor would not start. Unfortunately, only the entire assembly was available on short notice so it was pretty pricey ($347 CAD). That cured it. The parts guy said they have sold lots of them, typically in the first two years.
Looking inside the motor, it is a permanent magnet AC motor with an overload switch inside. The DC resistance on mine was 7.4 ohms which was within spec, so I suspect the overload switch inside the motor itself, which is a Klixon 3mp21904 - actually available on Taobao but it will take 10 years to get here...saving the old one in case it fails again.