What does UN error mean on samsung UL2157?

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ERROR CODE        │ UN
BRAND             │ samsung
MODEL             │ UL2157
FAULT TYPE        │ System Error
FIX DIFFICULTY    │ Moderate
USER FIX POSSIBLE │ No

The UN error on the samsung UL2157 washing machine indicates a System Error—the main control board (PCB) is not functioning correctly. In most cases, a power reset resolves the issue. If the error persists, follow the troubleshooting steps below.

Possible Causes

Cause	Type	Probability	User Fix
main control board (PCB) malfunction (Official)	Hardware	High	No
Wiring connection issue (Official)	Electrical	Medium	No
Sensor fault (Official)	Electronics	Medium	No
Control board issue (Technician note)	Electronics	Low	No

Troubleshooting Steps

⚠️ Safety first: Disconnect power before touching any wiring or internal components. This appliance operates at mains voltage (220-240V).

1. Reset the machine — Turn off, unplug from mains, wait 60 seconds, plug back in and restart.
2. Ensure door is properly closed — Press the door firmly against the door frame.
3. Check for visible obstructions — Inspect the door seal and lock area for debris or damage.
4. Inspect wiring connections — With power disconnected, check the relevant connector is firmly seated.
5. Test the component — Use appropriate tools to test the main control board (PCB).
6. If steps 1–5 don’t resolve the issue, contact a qualified technician to test and replace the main control board (PCB).

Frequently Asked Questions

How do I reset the UN error on my samsung UL2157?

Unplug the machine from the mains, wait 60 seconds, then plug back in and restart. This clears temporary glitches. If UN reappears, a hardware issue requires professional diagnosis.

Why does my samsung washing machine keep showing UN?

Recurring UN errors indicate a persistent fault with the main control board (PCB). The error will continue until the root cause is identified and repaired.

Can I fix the UN error myself?

Basic troubleshooting like power reset is DIY-safe. However, system error requires testing internal components with specialized tools. Professional service is recommended for proper diagnosis and repair.

My samsung washer shows UN but it was working fine before—what changed?

This error can indicate a fault that is not immediately visible, such as an internal component failure. Document when the error appears and contact a qualified appliance technician with the exact error code for faster diagnosis.

Source

Source: samsung UL2157 Service Manual
Last verified: 2026-02