Bosch Dishwasher Error Code 4

Error code 4 on a Bosch dishwasher signals a water filling fault. The control board opened the inlet valve but did not detect that the tub filled to the required level within the expected time. The problem typically originates in the water supply path, including the household shutoff valve, inlet hose, or the inlet valve itself.

You should not continue running the dishwasher with E4 active. The machine halted the cycle because it could not confirm adequate water in the tub. Running a wash or drain cycle without proper water fill risks damaging the circulation pump and heating element, both of which require water for lubrication and cooling. Resolve the fill fault before running another cycle.

E4 is a protective fault, not a catastrophic failure. In many cases it has a simple cause like a closed valve or kinked hose that costs nothing to fix. Even if the inlet valve needs replacement, it is a relatively accessible repair. The code becomes more costly only if the fault was ignored and the pump or heating element sustained damage from running dry, which is why the machine stops and displays the code rather than continuing.

Start by checking that the household water supply valve is fully open and that the inlet hose has no kinks or visible blockages. If water supply is confirmed good, remove the inlet hose and inspect the inlet valve screen for mineral buildup or debris, cleaning it if clogged. If those steps do not clear the fault, test or replace the water inlet valve, and if the valve tests functional, inspect the pressure switch and its hose for blockages or cracks.

If the fix is simply opening a closed shutoff valve or straightening a kinked hose, the cost is zero. A replacement water inlet valve for a Bosch dishwasher typically costs between 25 and 60 dollars in parts, and is a moderate DIY repair requiring disconnection of the water supply and removal of the door panel. A pressure switch runs roughly 20 to 50 dollars. If hiring a technician, expect a diagnostic fee plus one hour of labor, bringing total repair costs to roughly 150 to 250 dollars depending on region and the part needed.