F02 is a fault code, which appears in Whirlpool washing machines to indicate slow or poor draining. This can be due to a clogged drain hose, suds in the tub, or faults occurring in various components, such as drain pump, control board, etc.
If you have noticed that your washer is not draining well, look into the tub and check it for suds. If there are, wait until it dissipates and rinse out the tub. To avoid this problem, use High Efficiency (HE) detergents. Do not exceed the amount of detergent, even if it is HE.
If there are no excessive suds, but the water is not draining properly, you need to check the draining system (drain hose, washer drain, etc.) for clogs and restrictions.
If there are no clogs, and the draining system is ok, there may be a problem in the drain pump. Not unlikely, it is faulty and needs to be replaced.
If the pump is all right, but the machine is still not draining well, there may be an issue in the electronic control board.
If the machine is draining well, but the code is there, most likely, you have a faulty water level pressure switch or control board.