Whirlpool Dishwasher Error Code FB

The FB code indicates a fault with the MDV, the diverter motor valve that alternates water flow between the upper and lower spray arms. The control board detected that the water inlet activated and the WI sensor changed state, but no confirmation signal was received from the MDV within 120 seconds. This points to a blockage in the sump, a failed motor, or an electrical problem in the circuit supplying 230V to the MDV.

It is not recommended. When the FB code is active, the diverter system is not functioning correctly, meaning one set of spray arms may not be receiving water and dishes will not be cleaned properly. Continuing to run cycles will not resolve the fault and could allow the underlying problem to worsen. It is best to diagnose and correct the issue before running additional cycles.

If the fix is simply clearing a blocked diverter disc, there may be no parts cost at all. Replacing the MDV diverter motor typically costs between 50 and 150 dollars for the part, plus labor if a technician performs the work. A control board replacement is more expensive, generally ranging from 100 to 300 dollars or more for the part depending on the model. Getting a confirmed diagnosis before ordering parts will help avoid unnecessary expense.

Some causes are DIY-friendly. Inspecting and clearing the diverter disc area in the sump for debris requires no special tools and should be the first step. Checking that the spray arms alternate approximately every 30 to 40 seconds can also be done without special equipment. However, measuring 230V at the MDV terminals requires a multimeter and comfort working near live voltage, so homeowners who are not familiar with electrical testing should call a qualified technician.

A reset may temporarily clear the code from the display, but the FB error will return as soon as the dishwasher runs a cycle and the control board again fails to receive a signal from the MDV within 120 seconds. The underlying mechanical or electrical fault must be corrected for the code to stay cleared.