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Samsung Dishwasher Error Code 4C: What It Means and How to Fix It

Samsung dishwasher guide · Decoded from manufacturer documentation · Safe homeowner checks only

What is happening inside the machine

A dishwasher cycle starts with a short drain, then a fill. The control board opens the water inlet valve, water flows through the inlet hose and a small filter screen into the tub, and a water level sensor watches the tub fill. The board expects the tub to reach its target level within a set time. Samsung describes 4C and 4E as water supply checks, and its own published checks start with the supply valve, a suspended water supply, and a frozen or clogged inlet valve or line. When the fill falls short, the board stops the cycle and shows 4C rather than washing with too little water, because washing with too little water would run the pump dry and hide the real fault. Two different failures can produce the same code. The water reaching the machine can be restricted, in which case the dishwasher is telling the truth about its supply. Or the supply can be good while the machine misreads it, because the inlet valve fails to open, the level sensor misreports the tub, or the board misjudges the fill. A useful early clue is the tub itself. A tub that stays completely dry points at a supply that never arrived. A shallow puddle that never rises points at restricted flow. A tub that fills to a normal level and still shows 4C points at the level sensor or the board, because the water was there and the machine failed to recognise it.

Finding the cause

The water supply valve to the dishwasher is closed or only partly open

The supply valve is the first check because it is the most common cause and the easiest to miss. The valve usually sits under the sink, and it may have been closed for plumbing work, a sink repair, or a vacation shutdown and then reopened only partly. A valve that is a quarter turn short of fully open can look open while restricting flow enough to fail the fill timing. Turn the valve fully to its open position and confirm the handle moves freely to its stop. On some installations the valve handle can break internally, so the handle turns while the valve itself stays shut: if the handle spins without resistance or feels detached, treat the valve as suspect and have it replaced by a plumber rather than forcing it. After opening the valve fully, run the reset and retest step. If 4C clears, the valve was the story. If the valve was already fully open, move on, because the restriction is further along the line.

The house water supply is suspended or under low pressure

A dishwasher cannot fill from a supply that is not there. Check whether water is running normally at a nearby tap, and whether a utility shutdown, a burst pipe repair, or work on the house plumbing has suspended the supply. Low house pressure has the same effect in a milder form: water arrives, but too slowly to meet the fill timing, so the board gives up and shows 4C. A tap that runs weakly throughout the house points at a house wide pressure problem, not a dishwasher fault, and no dishwasher part will fix it. The test that settles it is simple and external: run a nearby cold tap at full flow and watch for normal pressure and a steady stream. If the whole house is weak or dry, wait for the supply to return to normal, or call a plumber for a house pressure problem, and retest the dishwasher only once the taps run normally. If house pressure is strong and steady, the restriction is specific to the dishwasher line.

The inlet hose is kinked, crushed, or fitted with a FloodSafe hose

The inlet hose runs from the supply valve to the back or base of the dishwasher, and it is easy to kink when the machine is pushed back after cleaning or installation. A hose folded sharply, crushed against the wall, or pinched by the machine feet restricts flow just as a partly closed valve does. Pull the machine out only as far as its connections allow, without straining hoses or the drain hose, and look at the inlet hose along its full visible length. A sharp bend, a flattened section, or a hose trapped under the machine all point at the hose. Straighten a kinked hose and retest. There is one hose type to check by name: Samsung warns that FloodSafe hoses are not compatible with its dishwashers, because the hose safety mechanism can restrict flow enough for the machine to read the supply as inadequate. If a FloodSafe hose is fitted, replacing it with a standard manufacturer approved hose is a legitimate check before suspecting any part. Never run the dishwasher with the inlet hose disconnected as a test: an open hose floods the kitchen floor in seconds.

The inlet filter screen is clogged with sediment or debris

Where the inlet hose meets the dishwasher inlet valve there is a small filter screen, and Samsung lists a valve or line clogged by foreign objects among its own 4C checks. Sediment from the house supply, scale, or debris stirred up by plumbing work can collect on that screen and choke the fill to a trickle. The symptom is distinctive: the valve opens, water enters slowly, and the tub never reaches its level in time. With the water supply valve closed and the machine switched off, a confident homeowner can disconnect the inlet hose at the valve end, remove the screen where the design allows it, and rinse it clean. Take care to refit the screen exactly as it came out, because running without it lets debris into the valve itself. If you cannot reach the screen safely, or if the connection is seized, leave it to a repair service: forcing a seized fitting cracks the valve body and turns a cleaning job into a valve replacement. Retest after cleaning. If 4C clears, sediment was the story, and a repeat clog within weeks points at a house water quality problem worth raising with a plumber.

The inlet hose or valve is frozen in cold weather

In an unheated kitchen, a garage installation, or a home left cold during a freeze, water in the inlet hose or valve can freeze solid. A frozen line delivers no water at all, so the tub stays dry and 4C appears promptly. The clue is timing: 4C that starts during a cold snap, in a machine against an outside wall or in an unheated space, with other cold taps also sluggish. Warm the area gently with room heat and a warm towel on the exposed hose, never with an open flame or a heat gun on a plastic hose, and wait until nearby taps run normally before retesting. Do not keep running fill attempts while the line is frozen: the pump and valve gain nothing from repeated dry attempts. If the line thaws and 4C clears, the freeze was the cause, and insulating the exposed hose run is the prevention. If it stays frozen or the valve is cracked and leaking after thawing, switch the supply valve off and call a plumber.

The water inlet valve has failed and will not open fully

When the house supply is strong, the valve is fully open, the hose is straight and approved, and the filter screen is clean, yet 4C persists, the inlet valve itself becomes the leading suspect. The inlet valve is an electrically operated valve that opens on the board signal and closes when the fill ends. It can fail in two ways: it can stick shut, so no water enters at all, or it can open only partly, so water enters too slowly to meet the fill timing. A valve that hums or clicks during the fill attempt but delivers no water is a useful observation to pass to a technician. Testing or replacing an inlet valve means working with the water connection and the machine electrics, so it is a repair service job for most owners, not a first part swap. The valve is also model specific: the wrong valve can fit physically while delivering the wrong flow rate, so the part must match your exact model. If a service confirms the valve, replacement usually ends the fault, and the retest is a normal full cycle with a normal water level.

The water level sensor or the control board is misreading the fill

The last suspects are the parts that judge the fill rather than deliver it. The water level sensor reports the tub level to the board, and if it sticks, drifts, or fails, the board can show 4C even while the tub fills normally. The signature is a tub that reaches a normal level yet still trips 4C, or a level that reads inconsistently from cycle to cycle. A control board fault is rarer and earns suspicion only when the supply, hose, filter, valve, and sensor have all been checked and 4C still persists. Board diagnosis needs component level testing that no external check can replace, and a board is expensive enough that guessing at it wastes money. If every check above passes and 4C persists, stop replacing parts and arrange a professional diagnosis, and tell the technician which checks you have already done so the visit starts at the sensor and board, not at the supply valve. Note also the code family: 4C that appears alongside a leak code such as LE is a different fault, and a machine that is actually leaking needs the supply switched off and a service call, not a fill diagnosis.

Fixing it

1. Confirm the house supply, about 2 minutes. Run a nearby cold tap at full flow. If the house supply is weak or suspended, fix that first and retest only once taps run normally.
2. Open the dishwasher supply valve fully, about 5 minutes. Find the valve under the sink, turn it fully to its open stop, and check the handle is not spinning freely on a broken stem. If the handle is broken, call a plumber.
3. Check the inlet hose, about 10 minutes. Without straining any connection, look along the visible hose for kinks, crushing, or a FloodSafe hose. Straighten a kinked hose, or replace a FloodSafe hose with a standard manufacturer approved hose.
4. Reset the dishwasher, about 10 minutes. Switch the dishwasher off, switch its breaker off for at least 1 minute, switch the breaker back on, and start a normal cycle. Watch whether water enters and how far the tub fills before any code returns.
5. Clean the inlet filter screen, about 20 minutes, only if you can reach it safely. With the supply valve closed and the machine off, remove the screen where the design allows it, rinse it clean, and refit it exactly as it came out. If the fitting is seized, leave it to a service.
6. Retest with a normal cycle, about 45 minutes. Run a full normal cycle and check that the tub fills, the wash runs without 4C, and the dishes come out clean with no standing water left behind.

What it costs

Supply checks first; valve second; sensor or board last. Most 4C cases end at the free supply checks. An inlet valve is the common part outcome, and a board is the expensive outcome that should never be guessed at.

All prices on this page are estimates based on typical US parts and service pricing. Your model, region and the actual failed part will move the real figure.

Repair or replace note: a valve or sensor repair is almost always worth doing, since the fitted cost is a small fraction of a replacement dishwasher. A board repair on an older dishwasher needs a harder look: if the board plus labour passes half the cost of a comparable new dishwasher, or if the tub, pump, and board all need work at once, replacement becomes the sensible choice. The same water supply naming appears on the Samsung washer 4C guide, drain problems are covered by the dishwasher not draining guide, and the full list is on the dishwasher hub.

Mistakes that make it worse

• Replacing the inlet valve before checking the supply. A closed valve, a kinked hose, and a clogged filter all mimic a failed valve, and all of them are free to find.
• Keeping a FloodSafe hose fitted while diagnosing. Samsung warns against these hoses on its dishwashers. Leaving one in place while replacing parts wastes a part and a visit.
• Running the dishwasher with the inlet hose disconnected. An open hose floods the kitchen in seconds and does not prove anything a tap test cannot prove safely.
• Forcing a seized inlet fitting. A cracked valve body turns a cleaning job into a valve replacement plus a water damage risk. Leave seized fittings to a service.
• Ignoring a real leak while chasing a fill code. If water is on the floor or under the machine, switch the supply off and call a service. A fill diagnosis does not apply to a leaking machine.
• Ordering a valve for the wrong model. Check the model number first: inlet valves are model specific, and the wrong valve can deliver the wrong flow rate and trip 4C again.

Frequently Asked Questions

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• Samsung Washer Error Code 4C: What It Means and How to Fix It
• Samsung Dishwasher Error Code OE: What It Means and How to Fix It
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