Smartphones based on the operating system Android have hidden functionality intended for engineers and repair specialists. This functionality is activated using special combinations of characters called service or engineering codes. These tools may seem complicated to the average user, but they provide access to deep system settings that cannot be found in the standard menu.
Entering such combinations is carried out directly through the standard “Phone” or “Dialer” application. This is a universal method that works on the vast majority of devices, regardless of manufacturer. Service code is a sequence of numbers and symbols starting with an asterisk and ending with a hash. After entering the last digit, the menu opens automatically; you usually do not need to press the call button.
However, you should understand that not all codes work on all devices. Manufacturers often modify firmware, blocking access to certain sections of the engineering menu for security or system stability reasons. However, basic commands for checking IMEI or battery status remain working almost everywhere.
The main input method is through the phone application
The simplest and most accessible method of activating hidden functions is to use the standard one. dialers. You don't need to download third-party apps or get root access. Just open the app you usually use to make calls. The interface may differ on different models Samsung, Xiaomi or Pixel, but the field for entering numbers is always present.
Dial a combination of characters, for example, *#06# to check the unique device identifier. As soon as you enter the last character (in this case, a hash), a pop-up window with information will instantly appear on the screen. Automatic start This is a key feature of most USSD commands and engineering menus.
If nothing happened after entering the full combination, try pressing the green call button. Some telecom operators or specific firmware versions require confirmation of sending the request. In rare cases, the system may display a message about a connection error or an invalid MMI code, which means that this function is blocked by the manufacturer.
⚠️ Attention: Entering some codes, especially those containing the word RESET or Factory, can lead to instant deletion of all data from the phone without the possibility of recovery. Be extremely careful when typing characters.
Before entering any service codes, write them down on paper or take a screenshot, so that in case of an error you can accurately repeat the sequence or find a description of the command on the Internet.
Alternative methods of accessing the engineering menu
Sometimes a standard dialer does not recognize the entered one combination. This often happens on devices with highly customized skins or in the absence of a SIM card. In such situations, third-party solutions come to the rescue. There are special applications in Google Playthat emulate entering codes or provide a convenient list of commands with quick launch buttons.
One of these tools is the application QuickShortcutMaker. It allows you to find hidden system activities by name. You will need to search for the section related to engineering testing in the application search and create a shortcut on your desktop. This method is especially useful when you need to get to a menu whose code is blocked by your telecom operator.
Advanced users can also enter commands via a computer using debugging via ADB (Android Debug Bridge). By connecting your smartphone to your PC and turning on developer mode, you can send intents commands that open the desired activities. This is the most reliable method if the phone's touch screen does not respond or the interface is blocked.
- 📱 Use third-party launchers or caller applications if the standard application blocks the entry of special characters.
- 💻 Connecting via ADB allows you to enter commands even when the touch screen is not working.
- 🔍 Search hidden activities through the system settings sometimes helps to find the desired section without codes.
Popular universal codes for diagnostics
There is a set of commands that are considered universal and work on most versions Android. They provide critical information about the state of the device. For example, code #0# is often used in service centers Samsung to run a full test of equipment. It checks the operation of the display, sensor, speakers and vibration.
A combination is used to check the battery status and charge information. ##4636##. This menu provides detailed battery usage statistics, Wi-Fi connection information, and phone information. Here you can see how stable the radio module is and whether there are any problems with connecting to the network.
The code *#06# is the most famous and safe. It displays the device's IMEI code, which is required when registering the phone with an operator or when checking the device for theft. This data is stored in protected memory and cannot be changed by the user through the normal settings menu.
| Command | Purpose | Risk level |
|---|---|---|
*#06# |
IMEI check | Safe |
##4636## |
Testing and statistics menu | Safe |
#0# |
Engineering menu (Samsung) | Safe |
##7780## |
Reset settings (without deleting media) | High |
Universal codes work on 90% of devices, but manufacturers can change their functionality in new firmware versions. Always check the operation of the code on safe examples before using critical commands.
Specific codes for different manufacturers
Each major brand makes its own changes to the structure of the engineering menu. Device owners Xiaomi and Redmi often use the code ##6484## to enter CIT (Customer Integration Test) mode. This menu allows you to test each hardware component separately, from the camera to the proximity sensor. Users can use the combination that opens the project menu. Logging settings, factory reset and software version information are available here. It is important to note that on new models with the EMUI shell, access to this menu may be limited.
Users Huawei And Honor can use a combination ##2846579##, which opens the project menu. Logging settings, factory reset and software version information are available here. It is important to note that on new models with EMUI shell, access to this menu may be limited.
Devices from Sony have their own unique diagnostic menu, called by the code ##7378423##. It provides access to service tests, configuration information and network status. The interface of this menu is usually more strict and technical compared to competitors.
⚠️ Attention: The interfaces and available functions in the engineering menus of different brands may vary significantly. What works on OnePlusmay not be available on Motorola.
Some manufacturers completely remove the ability to enter codes through the dialer in the latest versions of their shells. In such cases, the only option is to use special applications from the store or connect to a computer. Always check the relevance of the codes for your specific model and version Android.
What to do if the code does not work?
If the universal code does not work, try adding an operator prefix (for example, before the asterisk) or check if you have custom firmware installed that could cut out this functionality.
Settings network and radio module through service codes
One of the most popular functions of the engineering menu is managing network modes. This is especially true in areas of unstable coverage, where the phone constantly switches between 3G and 4G, draining the battery. Through the menu ##4636## you can force select your preferred network type.
In the “Phone Information” section, find the “Set up preferred network type” drop-down list. You can select LTE Only mode to lock the connection to 4G. This is useful for stable Internet, but remember that in this mode, incoming calls may not go through if VoLTE technology is not configured.
The “Switch radio” function is also available here. If your network is lost and rebooting does not help, you can try turning off and turning on the radio module programmatically through this menu. This acts as a soft reset of the modem without completely rebooting the operating system.
- 📶 "LTE Only" mode increases Internet speed, but may block voice calls in areas without VoLTE.
- 🔄 Restarting the radio through the menu helps restore communication without losing open applications.
- 📡 Viewing the signal level in dBm allows you to accurately assess the quality of coverage at a specific point.
Precautions and risks of use
Engineering menu is a powerful tool that gives access to the “insides” of the system. Careless changes in parameters can lead to unstable operation of the device, loss of connection, or even turning the smartphone into a “brick”. Never change settings whose purpose you do not know.
Reset commands are especially dangerous. Some codes initiate a full factory reset (Hard Reset) instantly, without additional confirmation. If you accidentally enter such a combination, it will be almost impossible to stop the process. Always check each digit before entering the last hash.
Changing sensor calibration or display settings may cause the sensor to not function correctly or colors to change. It can be very difficult to restore factory calibration data without contacting a service center. Use these functions only as a last resort when standard settings do not help solve the problem.
⚠️ Attention: Manufacturers are not responsible for problems caused by interfering with the system through engineering codes. The use of these tools is at your own risk.
☑️ Safe code entry
Frequently asked questions (FAQ)
Will the entered codes be visible in the call log?
Usually service codes are not stored in call history, since they are not full-fledged calls. However, some phone models may display them as outgoing calls with a number consisting of asterisks and numbers. This depends on the specific firmware version and phone application.
Is it possible to enter a service code without a SIM card?
Yes, most engineering codes work autonomously and do not require a SIM card or connection to the operator's network. They access the device's local software. The exception is USSD requests, which actually require communication with the operator's server.
What to do if the phone rebooted after entering the code?
If the device rebooted immediately after entering the command, you may have activated a critical system process or encountered a firmware error. After switching on, check the functionality of the main functions. If the problems persist, you may need to reset the settings through the Recovery menu.
Do these codes work on Android tablets?
Yes, if the tablet has the “Phone” application or the ability to emulate a call, the codes will work. On tablets without a cellular module, the functionality will be limited to only those commands that do not require access to the radio module (for example, screen or battery tests).
Can you unlock your phone with codes?
No, service codes are not intended to unlock the screen or remove the Google account lock (FRP). Attempts to find such codes on the Internet often lead to downloading malware. Unlocking requires other methods not related to the engineering menu.