The situation when a modern smartphone suddenly loses connection with the cellular network causes natural irritation and anxiety in the user. This is especially acute if there are important calls left on your balance or a mobile data subscription is active MTS. The problem can manifest itself in different ways: from the complete absence of a network icon to the message “No SIM card” or “Insert SIM card” in the notification shade. Most often, the reason lies not in equipment failure, but in a software failure or banal oxidation of contacts.
Before running to a service center or communication store to replace the media, it is worth conducting independent diagnostics of the device. In most cases, restoration of functionality takes only a few minutes and does not require special skills. We will consider the algorithm of actions from the simplest steps to more complex interventions in the system Android. It is important to understand that ignoring the problem may result in the phone no longer receiving emergency calls.
Basic diagnostics and physical check of contacts
First of all, it is necessary to exclude mechanical causes of loss of communication. Even a microscopic layer of dust or grease on the chip's gold contacts can disrupt the electrical connection to the smartphone's tray. Carefully remove the tray using a paper clip or a special key. Take a look yourself SIM card: it should not have deep scratches, cracks or signs of corrosion. If the plastic has turned yellow or the contacts have darkened, this is a sure sign that the operator needs to replace it.
Take a soft, lint-free cloth or a regular school eraser and carefully wipe the contact pad of the chip. Do not use alcohol or aggressive solvents if you are not sure about the durability of the paint on the plastic. Also check the phone tray itself: there should be no debris, lint or moisture inside it. Sometimes the tray is not inserted all the way or is warped, causing the contacts to simply not close.
⚠️ Attention: Never try to force the tray in if it encounters resistance. This may break the ejection mechanism or damage the internal pins of the reader inside the smartphone case.
Try installing the SIM card in a different slot if your smartphone supports two active numbers. This will help you understand whether the problem is in a specific connector or in the card itself. If the network appeared in the second slot, it means that the first connector could have oxidized or failed. If the phone does not see any of the two cards, the problem is most likely software or related to the communication module.
☑️ Initial check of the SIM card
Soft reset and reboot of network modules
Operating system Android sometimes makes errors in the operation of the radio module drivers. Simply rebooting the phone often solves the problem, as it completely resets the state of all temporary processes and reinitializes the hardware. However, if the usual power cycle does not help, it is worth trying a more in-depth procedure for restarting network services.
Turn on and off Airplane mode. Wait about 10-15 seconds in the off state and then turn it on again. This action forcibly reconnects the smartphone to the nearest operator base station MTS. If the network icon appears, but the Internet does not work, the access point settings may have gone wrong APN.
For a more drastic solution, you can reset the network settings. This operation will not delete your personal files, photos or contacts, but will return your mobile network settings to factory defaults. The path to this function may differ depending on the manufacturer's shell, but usually it is located in the section Wi-Fi, Bluetooth and mobile networks. The path to this function may vary depending on the manufacturer's shell, but it is usually located in the section Settings → System → Reset settings → Reset Wi-Fi, mobile data and Bluetooth settings.
What happens when you reset network settings?
When performing this operation, the phone will forget all saved passwords from Wi-Fi networks and paired Bluetooth devices (headphones, watches). You will have to re-enter the passwords, but this often eliminates communication protocol conflicts that prevent the SIM card from working.
After performing the reset, the phone will automatically reboot. Try making a test call or sending SMS. If the device again writes “No network,” proceed to check the compatibility of frequency bands and operating mode.
Setting the network mode and selecting an operator
Sometimes the smartphone tries to connect to a network type that is not supported in a particular area or is outdated. For example, if you are in an area where the coverage 4G is unstable, and the phone persistently searches only for this standard, it may lose connection completely. It is necessary to switch the device to automatic selection mode or force the selection of an available standard.
Go to the mobile network settings via the path Settings → Connections → Mobile networks → Network mode. Select the "Auto (LTE/3G/2G)" or similar option. If this does not help, try temporarily limiting the connection to standard only 3G or 2Gto check if registration appears online. This will confirm that the radio module is working, but there are problems with the new generation signal.
- 📡 Make sure that the “5G Only” mode is not activated in the settings if there is no coverage of this standard from MTS in your area.
- 🔄 Try manually selecting an operator in the menu
Settings → Mobile networks → Telecom operators, unchecking the "Select automatically" checkbox. - 🔋 Check if the power saving mode is enabled, which can turn off the radio module to save battery charge.
Manually selecting an operator may take some time, as the phone will scan all available frequencies. If MTS RUS or MTSappears in the list, select it. If the list is empty or the selection does not bring results, the problem may be deeper.
Software update and IMEI check
A critically important diagnostic step is checking the hardware ID IMEI. If the phone does not see the SIM card, the radio module firmware may have crashed and the device has lost its serial number. To check, dial the universal code *#06#into your phone. The screen should display a unique number for your device.
If instead of numbers you see dashes, zeros or the message "IMEI null", this indicates a serious software failure or partition damage EFS (on Qualcomm processors) or NVRAM (on MediaTek). In this case, the software network settings will not help; you will need to reflash the phone at a service center.
| Symptom | Possible cause | Solution |
|---|---|---|
| IMEI is displayed correctly | Problem with contacts or settings | Cleaning the tray, resetting network settings |
| IMEI is not displayed (zeros) | Radio module firmware update | Restoring software in the service |
| The phone sees the card, but there is no Internet | Incorrect APN settings | Manually creating an access point |
| Constant network search | The antenna module is damaged | Replacing the antenna or cable |
It is also worth checking for updates for the operating system itself. Smartphone manufacturers regularly release patches to correct communication errors. Go to the Settings → About phone → System update section and click "Check for updates". Installing the latest version Android can eliminate driver conflicts.
The absence of an IMEI code when dialing *#06# is the most alarming signal, indicating damage to the phone's software, and not a problem with SIM card.
Settings conflicts and third-party applications
In rare cases, user-installed applications create a problem. Various “optimizers,” “antiviruses,” or task managers may mistakenly block access to telephony, considering it to be suspicious activity. Applications for recording calls or changing voices that have deep access rights to the system may also conflict.
Try loading your smartphone into Safe Mode. In this mode, only system applications are launched. The method of entering depends on the model: usually you need to hold down the power button on the screen, and then press and hold the "Power off" icon on the display until you are prompted to enter safe mode. If the SIM card works in this mode, then one of the installed applications is to blame.
⚠️ Attention: In Safe Mode, some functions may be limited. Do not be alarmed if the icons of installed games and apps become translucent or disappear from the desktop - this is normal system behavior.
If you have recently installed new apps, remove them one by one, checking the connection after each removal. Pay special attention to applications that require permission to access your phone and SMS. Sometimes it helps to clear the data of the system application "Phone" or "SIM Services" in the section Settings → Applications.
Before deleting system updates or resetting settings, make sure that you have a backup copy of important contacts, since some older phone models store them directly in the SIM card memory, which may be damaged.
When a SIM card replacement or a service visit is required
If all of the above methods do not bring results, there is a high probability of physical wear and tear on the plastic card itself. SIM cards have a limited memory rewrite resource and contact life. Over time, the chip degrades, especially if the phone is often overheated or exposed to a humid environment.
For subscribers MTS card replacement is free in most communication stores with a passport. The new card will have the same number and balance. This is the fastest way to rule out media failure. If replacing the card with a known good one (you can ask a friend to insert his card into your phone) does not help, the problem is definitely in the smartphone.
In the event of a hardware failure, such as the antenna cable falling off after a fall, oxidation of the board from moisture or failure of the radio part, independent repair without special equipment is impossible. Diagnostics is required at a service center using a multimeter and programmers.
FAQ: Frequently asked questions
Why does the phone see the MTS SIM card, but does not pick up the network abroad?
You probably have the “Roaming” service disabled in your phone settings or on the number itself. Check in your MTS personal account for connected travel options and make sure that the “Data Roaming” checkbox is enabled in the mobile data settings.
Can a magnetic case affect the operation of a SIM card?
Yes, powerful magnets in book-cases or holders can interfere with the smartphone’s antenna, especially if it located close to the back cover. Try removing the case and checking the signal level.
What to do if the phone says “Network blocked”?
This message means that the phone is locked to a specific operator (for example, brought from abroad). To work with an MTS card, you will need an unlocking procedure (unbinding from the operator), which is done in specialized services.
Does a discharged battery affect the reading of a SIM card?
When the battery charge is critically low (less than 5%), the smartphone can turn off energy-intensive modules, including the radio transmitter, to save energy. Charge the device to 20-30% and check the connection again.
Will resetting the settings delete my photos and music?
No, resetting the network settings (Reset Network Settings) affects only the connection settings. Your personal files, media and contacts will remain safe. However, a full reset to factory settings (Factory Reset) will delete everything.