DIAGNOSIS PF means Power Failure. The machine lost power mid-cycle and is now locked out as a safety precaution.
FIX Unplug the washer from the wall outlet for a full 60 seconds. Plug it back in. The PF code should clear, and you can restart your cycle by pressing Start.
IF THAT DIDN'T WORK Check your home's circuit breaker or GFCI outlet. If the outlet lost power, reset the breaker or GFCI. Also, ensure the power cord is fully and securely plugged in.
HEADS UP You'll need to restart your wash cycle from the beginning. The machine won't resume where it left off.