How do I fix an F21 or F02 error code on my Whirlpool Duet washer?

First, press the Pause/Cancel button to clear the error. If that doesn't work, unplug the washer or disconnect the power for 5 minutes, then plug it back in and re-select your cycle and press Start. If the error persists after checking that the drain hose is not kinked or clogged and you are using HE detergent, call for service.