"F06" is a Motor Speed error code. This is an indication that there is a problem with the Drive Motor, Tachometer, Motor Control Unit (MCU), Central Control Unit (CCU) and/or interconnecting wiring between the all these components. The following link explains:
I would begin by checking all the connector plugs between the CCU, MCU and Drive Motor to ensure none of them are loose or have corroded contacts.
Read through the link and follow the steps provided. If you have questions, please let me know. I hope this helps.
NOTE: The majority of the time this failure is attributed to a bad tachometer which is located on the MCU. If defective, the MCU must be replaced. There is a technical data sheet that comes with the washer. It is located inside the washer behind the lower toe panel directly below the door. The panel comes off by removing the screws located under bottom front edge of the panel. With the screws removed, the panel will drop down, then come off. If the tech sheet is not located directly behind the panel, it will be affixed to one of the interior cabinet walls. Included are all the diagnostics and troubleshooting advice for your washer, including diagrams to show test points. HINT: For better access to the screws you can prop the two front feet of the washer up using a 2 x 4.