Hello, my name is Dave. The F6 code is listed as a problem with the MW relay. Here are the testing steps from the technical literature. The relay that is mentioned is a part of the control so if the problem continues you will need to replace the control.
1. Unplug microwave oven or disconnect power.
2.Check the cable to Relay 4903.
Check to see if the relay (4903 on relay electronic control) contact has welded closed.
Replace all parts and panels before operating.
Plug in microwave oven or reconnect power.
If problem persists, unplug microwave oven or disconnect power.
Replace electronic control.
Hello Patti. There really is not much to check other than the wires that go to the relay and they are almost never the problem. It is almost always the control. If it give the F6 code anytime you try to run the oven you will need the control. I looked up the control and it is #W10211457 ($105) if the last number in the model number is a 0 or a 1. If it is a 2 the number is #W10350619 ($80). After pulling the plug you can take off the top grille bu removing 2 screws. This exposes one screw at the top of the control panel and the panel will drop down. There are several connections and several screws that hold the control in place. It is best for a service person to do this because a microwave can cause electrical shock even after being unplugged if get near the capacitor.