F6 error code for this model indicates a drive motor tachometer error. The control board is unable to properly detect the motor speed. If you have a volt/ohm meter I can give you a few checks that will help you diagnose the problem. Always unplug or de-energize electrical equipment before removing covers or attempting service. Be careful and wear appropriate hand protection when working around sharp metal parts. You will need to gain access to the MCU (Motor Control Unit), and measure the motor windings . MCU connection should be as it is in your washer, there should be 5 black wires and 1 green wire. The black wires are as follows, pin 1 on top and pin 5 on the bottom . Set your meter to read resistance and check pin 1 to pin 2, pin 1 to pin 3, and pin 2 to pin 3, these should all read approximately 5 io 6 ohms. Next check pin 4 to pin 5, it should read approximately 115 to 125 ohms. If any of these readings are not very close to the values I have given you, check continuity on the wires from the MCU to the drive motor. If the wires check good, the drive motor is bad and will need to be replaced. If all readings are close to the values I gave and there is not an issue with the wires the MCU will need to be replaced.
Before doing anything else, try this fist : Another Tech has discovered that by just unhooking the the 2 green ground wires at the motor, the washer runs just fine- the tub, body and the rest of the machine is still grounded.
If the machine keeps filling with the power off, it will mean the water valve (s) are faulty. If it only overfills when using the machine, it has to be in the pressure system. Check that the bell (where the bottom of the air tube fits on the tub) is not blocked and that there are no kinks or damage to the tube. The machine has to be empty when changing any part of the pressure system or it will flood again.