Fb marks the spray arm divider position contact as always closed or open. The wash continues.
Model compatibility: Viking reuses codes across series and model years, so Fb / L1+L6 may mean something different on another appliance or generation. Confirm this against your model’s documentation and record your full model number before acting.
Plain language
What this code means
Fb is a spray arm divider fault where the position contact is continuously closed or open; the program proceeds and the fault is shown only in the service menu.
That small b is deliberate. Fb closes the fault list for Viking DFUD dishwashers, with L1 and L6 lit together on LED models. The subject is the spray arm divider, which sends water to the various spray arms as a program runs.
The condition
A position contact on the divider lets the control know its location. With this fault the contact is permanently closed, or permanently open, and does not change. The control therefore has no confirmation of the divider travelling between positions. Even so the program proceeds; the indication is limited to the service menu.
Checks named in the manual
Spray arm divider, the moving part changing the water path
Function of gear box, which drives the divider
Contacts, reporting its position
Wiring, which links back to the control
Owner notes
No symptom is described in the manual. One arm might receive more water than another if the divider cannot change position, yet Viking does not claim this, so anything you observe is for the technician’s information and is no diagnosis. Troubleshooting does say that spray arms need to rotate freely and dirt can clog their holes; looking costs nothing. Gear box and contacts sit inside the machine, so they are left to a technician.
Other service-menu or divider codes
F9: the circulation pressure fault, which is likewise service-menu only.
1-4: a diverter timeout, used by the newer series.
Viking dishwasher service in Los Angeles
Call (310) 692-1112 for Viking dishwasher service in Los Angeles if Fb appears. Spell it as capital F, small b, and give the model number. See the dishwasher service page.
Important safety warning. Do not attempt repairs involving electrical components, gas, water lines, refrigerant or sealed systems. Unplug the appliance if it is safe to reach the outlet, and leave internal diagnostics to a qualified technician.
Seeing this code on your Viking appliance?
Book a specialist visit for a clear estimate and approval before any repair.
