Diagnosis
nF is a no-fill error. Low water pressure or a clogged inlet valve screen. The washer times out waiting for enough water.
How to Fix It
Turn off both hot and cold water supply valves. Disconnect the fill hoses from the back of the washer. Check the small mesh screens inside the valve ports on the washer. Use needle-nose pliers to gently pull them out. Rinse them clean of sediment. Reinstall. Also check your household water pressure.
If That Didn't Work
The water inlet valve itself (part DC92-01583A) could be failing. The solenoid coils can weaken. This requires a multimeter test and replacement.
Heads Up
Always use the supplied rubber hoses with mesh filters. Never use old, braided steel hoses without checking for an integrated filter. Sediment will kill the valve.