What Is Samsung Washer Diagnostic Test Mode?
Samsung washing machines have a built-in diagnostic test mode (also called Self Test or Smart Check) that lets you test individual components — the water inlet valve, drain pump, motor, heater, and more — without dismantling anything. It's the fastest way to confirm exactly what's wrong before calling a technician.
What You Can Test in Diagnostic Mode
- Water inlet valve (hot and cold separately)
- Drain pump motor
- Door lock mechanism
- Drum motor and spin function
- Heating element
- Tub water level sensor
How to Enter Samsung Washer Test Mode (Front-Load)
Note: The exact button sequence varies by model. Always check your model's manual. The most common method for Samsung front-loaders is:
- Make sure the washer is empty and the door is closed.
- Turn the washer on but do not start a cycle.
- Press and hold Temp + Spin simultaneously for 3–5 seconds until "Cb" or "tSt" appears on the display.
- Press Start/Pause to begin the automated diagnostic sequence.
- The machine will cycle through each component automatically, displaying a code if it detects a fault.
Samsung Top-Load Washer Diagnostic Mode
- Turn the washer on with no laundry inside.
- Press and hold Delay End + Soil Level (or Spin + Soil Level on some models) for 3 seconds.
- "tSt" will appear on the display.
- Press Start to run the full test.
Reading Diagnostic Results
After the test completes, the display will show error codes for any failed components. Common codes include:
- 4E / 4C — Water supply issue. See our Samsung 4E/4C error code guide.
- 5E / 5C — Drain pump fault
- dE / dC — Door lock fault
- UE / UC — Unbalanced load or calibration error
- HE / HC — Heating error
How to Exit Diagnostic Mode
Press and hold the Start/Pause button for 5 seconds, or simply turn the washer off using the power button.
Samsung Smart Check App
Newer Samsung washers also support the Samsung Smart Check app. Simply hold your smartphone camera up to the washer's display and the app will read the error code and provide troubleshooting steps automatically.
When to Call a Pro
Diagnostic mode tells you what is wrong, but most component replacements — inlet valves, pumps, drum bearings, control boards — require a certified technician. If your Samsung washer is showing a fault code after diagnostic, contact AWS Domestic Appliance Repairs for same-day service in Atlanta.
🔧 AWS Domestic Appliance Repairs specialises in Samsung washer diagnostics and repair. Call (833) 747-4838 for same-day service in Atlanta.