Introduction: What is *#0*# Diagnostic Tool in Samsung Phones?
Samsung *#0*# Diagnostic Tool Not Opening on Your Phone? Here’s the REAL Fix (2025)
If you typed *#0*# in your Samsung dialer and nothing happened, you’re not alone. This hidden Samsung diagnostic tool is designed to open a powerful hardware test menu — but on many recent devices, it doesn’t work right away. In this guide, you’ll learn exactly why the *#0*# diagnostic tool fails and step-by-step fixes that actually work in 2025, even if you’re using One UI 6, carrier-locked firmware, or a newer Samsung model.
⚠️ Important: The
*#0*#diagnostic tool works only on Samsung’s default Phone app and does not work on Google Dialer.
Table of Contents
How to Fix *#0*# Not Working on Samsung
- Turn Off Auto Blocker (Security & Privacy) — many phones block USSD codes otherwise. XDA Developers
- Use Samsung Phone app (not Google Phone) — some dialer apps don’t support secret codes. Reddit
- Try Samsung Members Support Diagnostics if the code still fails.
Samsung smartphones are packed with hidden tools meant for testing hardware. Among these, one of the most powerful and secret tools is the diagnostic code *#0*#. Samsung engineers rely on this diagnostic tool for factory testing.
Samsung’s hidden code *#0*# remains one of the most powerful diagnostic tool in 2025 and heading into 2026. Originally designed for factory testing, this code opens a secret menu that lets you check your screen, camera, sensors, vibration, and speakers — all without downloading an app.
While intended for technicians, regular users now use it to verify hardware after repairs, drops, or battery issues. Not all Samsung devices support it, and carrier locks or software restrictions may block access.
For supported models, *#0*# is a safe and reliable way to ensure your phone is working properly. If you want even deeper testing, other Samsung secret codes like *#06# for IMEI or *#1234# for firmware info are still active and useful in 2026.
*#0*# is Samsung’s most powerful diagnostic tool, unlocking a hidden menu to test your phone’s hardware — from screen and camera to sensors and speakers. In this guide, you’ll learn how to use *#0*# in 2025, what it does, and which devices support it.
By simply dialing *#0*# on your phone’s keypad, you can access a deep diagnostic menu that allows you to test:
- Screen colors
- Touch sensors
- Camera modules
- Vibration motors
- Sensors like accelerometer and gyroscope
- Speakers and more
Originally designed for technicians, this code has become a valuable trick for regular users who want to check if their phone is working properly — without downloading any app.
Why Samsung Created *#0*#: The Real Purpose
The *#0*# diagnostic tool wasn’t made for normal users — it was built for:
- Samsung service engineers
- Factory testing before shipment
- Technicians performing repair diagnostic tool
- Advanced users troubleshooting hardware issues
Today, many users have discovered this code and use it to test their devices after drops, repairs, or battery issues.
How to Use *#0*# on Your Samsung Device
Here’s a simple step-by-step guide:
- Open your Phone app.
- Go to the dialer (keypad).
- Type this code:
*#0*# - As soon as you type the last “#”, a hardware diagnostic menu will appear — no need to press “Call”.
If nothing happens:
- Your phone may not support it (we’ll cover that below)
- Your carrier or region might have blocked it
- Your Android version might have disabled it
Samsung Devices That Support *#0*# in 2025
This code is confirmed working on many Samsung models, including:
🔹 Samsung Galaxy S Series:
- Galaxy S21 / S21+ / S21 Ultra
- Galaxy S22 / S22+ / S22 Ultra
- Galaxy S23 / S23+ / S23 Ultra
- Galaxy S24 / S24 Ultra (some variants)
🔹 Samsung Galaxy Note Series:
- Galaxy Note 10 / 10+
- Galaxy Note 20 / 20 Ultra
🔹 Samsung Galaxy A and M Series:
- Galaxy A52, A72, A73
- Galaxy M31, M33, M53, etc. (varies by region)
🔹 Galaxy Fold & Flip:
- Some features may work partially on Fold 4, Fold 5, Flip 5
💡 Note: Carrier-locked phones (e.g., Verizon, AT&T) might block this feature.
What You Can Test Inside *#0*#: Full Menu Breakdown
Once inside the #0# menu, you’ll see a grid of options. Here’s what each one does:
1. 🔴 Red / 🟢 Green / 🔵 Blue:
- Test for dead pixels or screen issues
- Tap each to see solid colors — ideal for display quality checking.
2. ⚪ Dimming:
- Test screen brightness levels and auto-dimming functionality
3. 📱 Touch:
- Test if all parts of the screen respond to touch
- You’ll be asked to draw lines over a grid — useful after a drop.
4. 🔈 Speaker:
- Tests your phone’s main speaker using a tone
5. 🔇 Vibration:
- Activates vibration motor instantly
6. 🎙️ MIC:
- Tests the microphone — will record and playback your voice
7. 📷 Camera:
- Opens camera module test (front & rear)
8. 🔄 Sensor:
- Test gyroscope, accelerometer, proximity sensor, light sensor
9. 🔆 LED:
- Activates LED flash to verify its functionality
10. 🛑 Others:
- Sub-tests like barometer, magnetic sensor, fingerprint sensor, etc. (depending on your device)
If you’re interested in exploring even more powerful and hidden smartphone codes beyond just *#0*#, check out our full guide covering all major brands.
👉 Smartphone Secret Codes 2025 – The Ultimate List for All Major Brands includes working USSD codes, hardware test codes, and advanced settings for Samsung, Xiaomi, Vivo, Realme, OnePlus, iPhone, and more.
Is *#0*# Safe to Use?
Yes, *#0*# is safe to use if you don’t modify or reset anything.
Safe Things to Do:
- Touch and test display, camera, mic, sensor
- Exit the menu safely
Unsafe if You:
- Access other engineering menus you don’t understand
- Try random secret codes like factory resets (
*2767*3855#) - Use it while phone is on low battery
🔁 To exit the menu, press the back or home button.
Devices Where *#0*# Might Not Work
Some users report *#0*# doesn’t open the diagnostic tool. This may happen due to:
- Carrier-locked phones (Verizon, AT&T, T-Mobile USA)
- Region-based software differences
- Android 14 or newer with restricted access
- Samsung Knox-enabled devices with restrictions
- Custom ROMs
Alternative Samsung Codes That Still Work (2025)
Here are other working secret codes in Samsung phones:
| Code | Function |
|---|---|
*#06# | Show IMEI number |
*#1234# | Check firmware version |
*#0228# | Battery status |
*#2663# | Touch firmware |
*#12580*369# | Hardware/software info |
*#0808# | USB settings |
*#7353# | Alternate quick test menu |
These codes also help with diagnostic tool and configuration.
⚠️ Warning: Some codes can access advanced system features. Only use them if you know what they do. Regular users should stick to non-intrusive codes like *#0*#, *#06#, or *#1234#.
Extra Notes / Updates for 2026
- Samsung continues to support most old secret codes, but newer devices with Android 13+ or One UI 6 may have some restrictions.
- Some carrier-locked devices disable certain diagnostic menus.
- Users can still verify hardware integrity (screen, sensors, camera, vibration) without external apps, making
*#0*#and other codes very useful for buying or repairing phones. - Feature expansion: Some newer devices even support battery health logs and thermal sensors via secret codes (
*#0228#updates).
FAQ – Samsung *#0*# Diagnostic Tool
Q1: Why is *#0*# not working on my Samsung?
It may be due to carrier lock, Knox restrictions, or Android 14+.
Q2: Is *#0*# safe to use?
Yes, it’s safe as long as you only test and don’t change settings.
Q3: Can *#0*# factory reset my phone?
No. It’s only a diagnostic tool. Reset codes are different and dangerous.
Q4: How to exit the *#0*# menu?
Simply press the back or home button.
Q5: Does *#0*# work on Galaxy Z Fold or Flip?
Partially — some diagnostic tool may not show properly due to display differences.
Final Thoughts: Should You Use *#0*#?
The code *#0*# is a hidden gem in Samsung phones. Whether you’re testing a used phone, verifying repairs, or checking your hardware — this tool gives you access to tests without needing apps or tools.
But always remember:
- Don’t press anything you don’t understand
- It’s a read-only mode for tests — not for settings or modifications
- Ideal for anyone buying/selling phones
Overall, *#0*# is one of the most useful tools Samsung users can access without any apps.
Bonus Tip:
Learn more about working mobile codes like *#0*# in our full guide.
If you’re interested in more hidden Samsung features like *#0*# or other smartphone secret codes, check out our full list of working codes here:
👉 Smartphone Secret Codes 2025 – The Ultimate List