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Samsung washing machine SUD error code – diagnosis and next steps

SAMSUNG · freestanding washing machine · based on 281 similar repairs

Diagnosed by Sean McCauley · SMC Services · Last verified 10 May 2026

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Likely causes (Samsung freestanding washing machine):

Problem summary

The SUD error code on Samsung freestanding washing machines indicates that the machine has detected excessive suds (foam) in the drum or pump system. When this happens, the machine typically stops the rinse cycle and locks the door. You may find you have to select the spin-and-drain cycle to unlock the door and empty the machine manually.

Likely causes

Based on 289 similar faults reported to SMC Services, the SUD error is most often caused by one of three issues:

Printed circuit board (PCB) fault – The control board may be misreading water levels or foam sensors, triggering a false SUD error even if suds are not excessive. This accounts for roughly one-third of cases.

Pump blockage or failure – A blocked or failing pump cannot drain water efficiently, causing suds to accumulate and trigger the sensor. This is the second most common cause (around one-quarter of cases).

Motor malfunction – A motor that is not running at the correct speed or not running at all will prevent proper water circulation and drainage, leading to foam buildup. This accounts for roughly one-fifth of cases.

Why this needs an engineer

All three likely causes involve sealed systems, electrical components, or moving parts that require specialist tools and training to diagnose and repair safely. The PCB, pump, and motor are not customer-serviceable items.

Do not attempt to disassemble the machine, access the pump directly, or replace any sealed-system components yourself. Work on washing machine electrics and sealed refrigeration or pump systems carries a risk of electric shock, water damage, and injury.

What to do now

  1. Note the error. Write down the error code (SUD) and the cycle where it appeared, along with when the fault started. This information helps an engineer diagnose the fault faster.

  2. Stop using the machine. Repeated attempts to run cycles may worsen a pump blockage or cause further damage to the motor or PCB.

  3. Drain the drum manually. If the door is locked, select the spin-and-drain cycle as you have already found. This will allow you to remove wet laundry safely.

  4. Call a qualified engineer. An engineer will test the PCB, pump, and motor to identify which component is failing and replace it if needed.

If you're in Northern Ireland, SMC Services can usually book a repair within 2–3 working days.

Step by step

  1. Warning sign: Repeated SUD errors after the first wash. If the SUD error appears on multiple different cycles or returns after the machine has been left switched off, this points to a hardware fault rather than a one-off suds buildup.
  2. Warning sign: SUD error with water still in the drum. If the error occurs and water cannot be drained even using the spin cycle, the pump is likely blocked or failed and needs professional inspection.
  3. Warning sign: Door remains locked after spin cycle. If the door lock does not release even after running the drain cycle, the fault may involve the door-lock mechanism as well as the suds sensor. Call an engineer.

Frequently asked questions

Can I just use less detergent to prevent SUD errors?
Using less detergent may help prevent suds in future washes, but it will not fix the underlying fault. If the SUD error is caused by a faulty PCB, pump, or motor, it will appear regardless of detergent amount. Have the machine checked by an engineer.
Will the SUD error go away if I leave the machine switched off?
No. The error code is triggered by a fault in the machine's components, not a temporary glitch. Switching the machine off and on again may clear the display, but the underlying problem will remain and the error will reappear.
Is it safe to ignore the SUD error and just use the spin cycle?
Using the spin-and-drain cycle to empty the machine is a safe short-term measure, but do not ignore the fault long-term. Continuing to run normal cycles will not resolve the problem and may lead to water leaks or further damage.
How much does it usually cost to fix a SUD error?
Repair costs depend on which component has failed. An engineer's initial visit includes a diagnosis fee. Once the faulty part is identified (PCB, pump, or motor), you will be given a quote for the replacement and labour. We recommend getting a diagnosis first.

Get this fixed

The parts most often needed for this repair — order direct:

Samsung Assy Sub Pcb (DC92-00599A) £91.33 SMC02412 View part → Samsung Assy Pcb Sub (DC92-00773G) £88.38 SMC02416 View part → Samsung Main Pcb (DC92-01119D) £144.83 SMC02421 View part → Samsung Drain Pump (DC31-00181A) £43.91 SMC02398 View part →
Browse all spares

Prefer a pro? A local appliance engineer can carry out this repair. SMC's own repair service covers Northern Ireland only. The parts above ship UK-wide.

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About the data on this page

This page draws on 281 similar repairs from across 29 years of SMC Services records — over 116,000+ appliance repairs in total since 1997. The likely-cause percentages above are computed directly from the engineer reports we filed for this brand and fault, and we update them as new repairs come in.

SMC Services Ltd · Registered in Northern Ireland, Co. NI628091 · Domestic & Commercial Appliance Repairs.