What do the error codes on my Whirlpool Duet washer mean?

F1 indicates a water supply issue—check hoses and valves. F2 indicates a drainage problem—inspect the drain hose for clogs. F3 indicates a temperature sensor error—contact service. F4 indicates a door lock malfunction—ensure the door is properly closed. Refer to the error code chart in the manual for specific troubleshooting steps.