Samsung Dishwasher 4C Error Code Water Supply Fill Fault

User question

Why does my Samsung dishwasher show 4C error code?

Artificial Intelligence Response

Direct answer to the question

Your Samsung dishwasher shows a 4C error code because it has detected a water supply/fill problem. In practical terms, the dishwasher is not receiving enough water, is receiving water too slowly, or the control system is not correctly detecting the incoming water.

On some Samsung models, the same fault may appear as 4E.

The most common causes are:

• Water supply valve under the sink is closed or partly closed.
• Inlet hose is kinked, crushed, frozen, or blocked.
• Mesh filter at the water inlet is clogged with sediment or scale.
• Household water pressure is too low.
• Water inlet valve inside the dishwasher is faulty.
• Flow meter, case-break assembly, pressure sensor, wiring, or control board fault.

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Detailed problem analysis

The 4C code is essentially a fill-time or water-flow fault. During the beginning of a wash cycle, the control board opens the water inlet valve and expects to detect a certain amount of water within a defined time. If the expected fill level or flow signal is not achieved, the dishwasher stops and displays 4C to prevent dry running, poor washing, heater damage, or flooding-related faults.

1. Water supply valve is not fully open

This is the first thing to check.

The shut-off valve is usually located:

• Under the kitchen sink,
• Behind the dishwasher,
• In an adjacent cabinet.

Make sure it is fully open. A partially open valve can allow a small amount of water through but not enough for the dishwasher to satisfy its fill requirement.

2. Inlet hose is kinked or restricted

The water inlet hose connects the household supply to the dishwasher. If it is:

• Bent sharply,
• Pinched behind the machine,
• Crushed during installation,
• Blocked internally,
• Frozen in a cold area,

then the dishwasher may not fill fast enough and will report 4C.

If the dishwasher was recently moved, installed, or the flooring/cabinetry was changed, a kinked hose is especially likely.

3. Clogged inlet filter screen

Samsung dishwashers typically have a small mesh filter screen at the water inlet connection. Its job is to stop debris from entering the inlet valve.

Over time it can become blocked by:

• Hard-water scale,
• Rust particles,
• Sand or sediment from plumbing,
• Debris after plumbing work.

A clogged screen reduces flow and can trigger the 4C code.

General procedure:

1. Turn off the dishwasher power.
2. Shut off the water supply.
3. Disconnect the inlet hose.
4. Locate the small mesh screen at the dishwasher inlet.
5. Clean it gently with water and a soft brush.
6. Reinstall it and reconnect the hose.
7. Check carefully for leaks.

Do not run the dishwasher without the filter screen installed, because debris can damage the inlet valve.

4. Low water pressure

Samsung dishwashers generally require adequate household water pressure, commonly around 20 psi minimum. If the pressure is too low, the machine may not fill within the allowed time.

Signs of low supply pressure include:

• Weak flow at the kitchen faucet,
• Sputtering taps,
• Slow-filling appliances,
• 4C error occurring when other fixtures are being used.

If possible, check pressure with a gauge. If the whole house has poor pressure, the problem may be with the plumbing, shut-off valve, pressure regulator, or municipal supply.

5. Faulty water inlet valve

The water inlet valve is an electrically operated solenoid valve. When the control board energizes it, the valve opens and allows water into the dishwasher.

It can fail in two ways:

Failure type	Symptom
Electrical failure	Solenoid coil is open circuit or out of specification
Mechanical failure	Valve coil tests okay, but the valve is stuck, scaled, or blocked

A technician or experienced DIYer can test the inlet valve using a multimeter. Typical resistance values vary by model, but many dishwasher inlet valves measure roughly in the hundreds to low thousands of ohms. An open-circuit reading usually indicates a failed valve.

If the dishwasher sends voltage to the valve but no water enters, the inlet valve is a strong suspect.

6. Flow meter, case-break, or sensor fault

Some Samsung dishwashers do not rely only on water level. They also monitor incoming water through a flow meter or case-break assembly.

A flow meter often contains:

• A small internal turbine,
• A magnet,
• A Hall-effect sensor,
• Wiring to the control board.

As water flows, the turbine rotates and sends pulses to the control board. If the turbine jams or the sensor fails, the dishwasher may actually be receiving water but still thinks no water is entering. That can also cause a 4C error.

A clue is:

• You hear water entering,
• The tub has water,
• But the dishwasher still stops with 4C.

In that case, the problem is less likely to be household water supply and more likely to be sensing, wiring, case-break, or control electronics.

7. Control board or wiring fault

Less commonly, the main PCB may fail to energize the inlet valve or may misread sensor signals.

Possible issues include:

• Loose connector at the inlet valve,
• Damaged wiring harness,
• Failed PCB relay or triac,
• Faulty sensor input circuit.

This is usually diagnosed only after the simpler water-supply checks have been completed.

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Practical troubleshooting sequence

Follow this order:

1. Cancel/reset the cycle

   • Hold Start/Reset for about 3 seconds, or turn power off for several minutes.

2. Check the water supply valve

   • Make sure it is fully open.

3. Inspect the inlet hose

   • Look for kinks, crushing, freezing, or sharp bends.

4. Check household water pressure

   • Run the kitchen faucet.
   • If flow is weak, solve the plumbing issue first.

5. Clean the inlet filter screen

   • Shut off water and power before disconnecting the hose.

6. Restart the dishwasher

   • Run a short/test cycle and listen for water entering.

7. If water does not enter

   • Suspect inlet valve, wiring, or control board.

8. If water enters but 4C still appears

   • Suspect flow meter, case-break assembly, pressure sensor, or control board.

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Important safety note

Before removing panels, disconnecting hoses, or testing electrical parts:

• Turn off power at the breaker or unplug the dishwasher.
• Shut off the water supply.
• Be prepared for water spillage when disconnecting the inlet hose.
• If the appliance is under warranty, avoid disassembly that could affect warranty coverage.

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When to call service

Call Samsung service or an appliance technician if:

• The water valve is open and the hose is not kinked.
• The inlet screen is clean.
• Water pressure is normal.
• The 4C error continues.
• The dishwasher fills but still reports 4C.
• You are not comfortable testing live voltage or internal components.

At that point, the likely causes are the inlet valve, flow meter/case-break assembly, sensor wiring, or main control board.

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Brief summary

A Samsung dishwasher displays 4C when it cannot fill correctly or cannot detect proper water intake. Start with the simple checks: open the water valve fully, inspect the inlet hose, clean the inlet filter, and verify water pressure. If those are all good, the fault is probably internal, most commonly the water inlet valve, flow sensor/case-break assembly, or related wiring/control electronics.

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