Samsung Washer UC Error Code — What It Means & How to Fix It

What Does This Error Mean?

The UC error on a Samsung washer means the machine has detected abnormal voltage from the power supply — usually voltage that is too low (under-voltage). Samsung washers need stable voltage to protect motors, electronics, and heating elements. This error is often triggered by power fluctuations, a brownout, an overloaded circuit, or a loose outlet connection. The washer stops the cycle to protect itself from low-voltage damage.

Affected Models

Samsung WF45R6100
Samsung WA50R5400
Samsung WF42H5000
Samsung WF56H9100
Most Samsung front-load and top-load washers

Common Causes

Home power supply is experiencing a brownout or temporary voltage drop
Washer shares a circuit with other high-draw appliances causing voltage sag
Loose connection at the wall outlet reducing effective voltage to the machine
Extension cord or power strip between the outlet and washer causing voltage drop
Failing main power control board misreading supply voltage

How to Fix It

Unplug the washer and wait 10 minutes, then plug back in and retry the cycle. If the error was caused by a temporary brownout or power dip, it will not return.

Power fluctuations from the utility company happen more often during hot weather when air conditioners are running heavily.
Make sure the washer is plugged directly into a properly grounded wall outlet — not an extension cord or power strip. Extension cords cause voltage drops that trigger UC errors.

Samsung explicitly states in its installation guides that extension cords must not be used.
Check what else is on the same electrical circuit as the washer. If a dryer, refrigerator, or air conditioner is on the same circuit, they may be causing voltage drops when they start.

Appliances draw the most power at startup — this is when voltage drops are most likely.
Test the outlet voltage with a multimeter. Acceptable range for North American washers is approximately 108 to 132 volts. Anything below 108 volts consistently means a wiring or utility issue.

Call your electricity provider if the voltage is consistently below spec — they are responsible for supply voltage.
If voltage tests fine and the error keeps returning, the main control board may be faulty. An appliance technician can confirm this with Samsung's diagnostic mode.

Control boards for Samsung washers typically cost $150 to $300 — confirm the diagnosis before purchasing.

When to Call a Professional

Persistent UC errors on a stable power supply indicate an electrical or control board problem that requires a technician. An electrician can measure the actual voltage at the outlet to determine if the supply is truly low. Do not attempt to modify the home's electrical supply — only a licensed electrician should do that work.

Frequently Asked Questions

What is the difference between UC and 9E on Samsung washers?

Both UC and 9E relate to power supply voltage problems. UC specifically indicates under-voltage — the supply is too low. 9E is a more general voltage irregularity code that can be too high or too low. The diagnostic steps are similar for both — check the outlet, circuit, and supply voltage.

Can a surge protector help prevent the UC error?

A standard surge protector only protects against high voltage spikes — it does not stabilize low voltage. To address brownouts and voltage fluctuations, you would need a voltage regulator or UPS (uninterruptible power supply). However, the first step is ensuring the circuit and outlet are properly sized for the washer.

Is UC error covered under Samsung warranty?

If the UC error is caused by a faulty control board within the warranty period, Samsung should cover it. If the cause is your home's electrical supply or user installation error (like using an extension cord), it is typically not covered. Contact Samsung support at 1-800-SAMSUNG with your model and serial number.