F6 E4 signals a problem with the float switch that monitors water level — specifically, the switch is remaining in the open position, which the control board reads as a potential overfill. An obstruction under the float, or a water inlet valve that will not fully shut off, are the two most common causes.
What F6 E4 means
The float switch sits in the bottom of the tub and rises with the water level. The control board expects it to move freely and return to its resting position between fills. If it stays in the open (raised) position, the board cannot confirm a safe water level and flags F6 E4.
Common causes
| Cause | How likely | What to look for |
|---|---|---|
| Debris or an obstruction under the float | Common | Food particles or a small item trapped beneath it |
| Float mechanically stuck | Common | Does not move freely by hand when the machine is unplugged |
| Inlet water fill valve not shutting off fully | Occasional | Water trickling in even when the dishwasher is off, leading to a genuine overfill |
How to fix it
- Locate the float switch
It sits at the bottom of the tub, usually a small dome-shaped part.
- Check for obstructions
With the machine unplugged, look for and remove any visible debris or food particles trapped underneath it, and confirm it moves up and down freely by hand.
- Check the water supply when the dishwasher is off
Listen and look for water trickling into the tub with the machine switched off. If the inlet valve is not shutting off completely, that is a genuine overfill risk and the underlying cause rather than the float itself.
When to call a professional
If the float moves freely with no obstruction and the water supply is confirmed to shut off properly, but F6 E4 persists, have a certified technician test the float switch and its wiring, or the water inlet valve, for a fault.
Stop and call a qualified appliance technician or electrician if you find scorched or melted wiring, smell burning, see water that has reached electrical components, or if the fault returns immediately after a repair. Never bypass a safety device — thermal fuses, door interlocks and flood switches fail for a reason, and defeating one converts a broken appliance into a fire or flood risk.
