Hi,Welcome to Just Answer, My name isXXXXX will be helping you with your appliance issue today.
Okay, let's see if we can get this into diagnostic mode,select any one button(except power, start, and stop) is and follow steps below, using the same button(remember the button)
press/hold 3 seconds> release for 3 seconds> press/hold 3 seconds> release for 3 seconds> press/hold 3 seconds.
If this test mode has been entered successfully, all indicators on the console are illuminated for 5 seconds with the 88 showing any estimated time remaining two-digit display,
if indicators do not display as described above the press/hold/release procedure above may not have performed within the time frame necessary for successful entry. Repeat step two to insure this was not the cause, if still unsuccessful, let me know, thanks, Bryan
Okay, F 51 flashes when there is a motor rotor position sensor (RPS) failure, this comes in a complete kit for this machine, I would love to say this is an easy job but unfortunately it is not, wish I had better news, truly this is better left to a qualified technician I know that's not what you want here but that is the answer to your issue, if you if wish here is a link to purchase the part, I wish I could be of more help,
http://www.repairclinic.com/PartDetail/Sensor-or-Thermistor/1394136?modelNumber=WTW6600SW2 thanks and well wishes, Bryan