What to check yourself
Step 1. Open the supply valve fully
Under the sink, the small valve feeding the dishwasher. Half open runs a slow fill that never beats the timer, which is why the machine can seem to work and then fail. If anyone has been working under that sink lately, start here.
Step 2. Clean the mesh screen inside the inlet valve
The check that fixes this for nothing, and the one almost nobody knows about. Turn the water off, unscrew the supply hose from the back of the machine and look into the fitting: there is a fine mesh screen catching grit from the pipework. An old toothbrush under a running tap clears it.
Shut the supply valve before undoing the hose and keep a towel handy for what is left in the line.
Step 3. Check whether the hose has an auto shutoff head
This one is specific to Samsung and worth knowing before you spend anything. Samsung advises against flood safe or auto shutoff supply hoses on their dishwashers: the mechanism inside restricts flow, and on a machine that fills in bursts it can trip and choke the supply, producing a fill fault with nothing actually wrong. A plain braided hose solves it. Look at the fitting at the tap end: an auto shutoff head is a fat plastic housing rather than a plain nut.
Step 4. Straighten the supply hose behind the machine
The braided line kinks against the wall when the machine is pushed back into its housing, which is why this fault so often shows up right after a kitchen job or a new floor.
Step 5. Check the pressure, especially on a well
Samsung asks for 20 to 120 PSI. Below that the fill is too slow to finish in time. If the kitchen tap is also weak, or the house is on a well pump, the machine is reporting a real problem that is not its own.
What a technician will look at
Described so you know what you are paying for, not as steps to repeat.
Test the inlet valve
If water reaches the machine and it still will not fill, the valve is the suspect, and a faulty coil in it is the most common single cause of this code. It is metered for resistance and checked for voltage while the cycle calls for water: voltage present and no flow means the valve, no voltage means the board.
When to call a technician
When the valve is open, the hose is plain and unkinked, the mesh screen is clean and the pressure at the nearest tap is normal, and 4C still comes back. What is left is live electrical testing next to a water connection.
What the repair costs
| Repair | Part only | Fitted by a technician |
|---|---|---|
| Opening the valve or straightening the hose | - | Free |
| Cleaning the inlet mesh screen | - | Free |
| Swapping an auto shutoff hose for a plain one | $15 to $35 | Free |
| Water inlet valve replacement | $25 to $80 | $95 to $300 |
A new machine of the same class runs $500 to $1,500. Once a quote passes about a third of that on an older appliance, the repair stops making sense.
Codes people confuse this with
Questions people ask
- What is the difference between 4C and 9E?
- 4C means no water arrived, or not enough of it, during the fill. 9E means water did arrive but the level dropped low during the wash. Different first suspects: 4C sends you to the tap, the hose and the valve, 9E to the level sensor, foam and whether the machine sits level.
- The tap under the sink runs fine. Why does the machine disagree?
- It measures level in the tub against a clock, not flow at the tap. Anything that slows the fill without stopping it, a half open valve or a silted up inlet screen, gives exactly this. The screen is the usual answer.
- Why does Samsung not want a flood safe hose?
- Because the safety head inside it reacts to the flow pattern of a dishwasher filling in bursts and can shut itself down. It is a hose designed for a washing machine. A plain braided line and a working shutoff valve do the same job without the false alarms.
Which machines this applies to
Applies to
Samsung dishwashers across the DW80, DW50 and Linear Wash ranges. Written 4E on older machines and 4C on newer ones for the same fault.
Last checked
2026-08-10