As with many appliance boards, relays that switch 120 VAC tend to create surge currents through the solder connections that attach the relays to the PC board. My dryer displayed a F01 also. After taking the control board out and examining the solder side of the board, it was immediately apparent that the solder joint for one of the relays had worn away and was causing arcing on the underside. I simply soldered a piece of 16 AWG wire in its place and the F01 issue is now resolved. Don't pay hundreds if dollars for a simple repair like this.