There are a number of reasons why a mobile phone or smartphone does not detect the presence of a SIM card. What are the most common causes of such a malfunction, and what to do under such circumstances? In most situations, the culprit that the phone does not see the SIM card is the device itself or the SIM itself.

What can be done?

The first step is to open the back of the phone case and remove the battery. This will give you access to the SIM card. There are several options why the smartphone does not see the SIM.

• There is a possibility that the device does not see the card, because it has shifted relative to the slot. In this case, the contacts of the chip and the sim receiver do not touch. What to do? Place the card in its original position.
• If the SIM card is not in close contact with the SIM receiver, you must use plain paper folded several times. This piece should be placed between the SIM card and the battery of the device, then close the back cover of the device and turn it on.
• Another reason that the phone does not see the SIM can be clogging of the contacts of the chip and the SIM receiver. If during the inspection traces of dirt or sand are found, it is necessary to treat such areas with an alcohol-soaked microfiber cloth or a regular eraser.
• You can also try to use any other working SIM. If a mobile phone or smartphone detects it, then the reason is in the card, and the device has nothing to do with it.

Problem in the device

Below are some of the most common cases when a smartphone or phone does not see a SIM card.

• The device is programmed for a SIM card of a specific operator. Often the price of imported mobile phones or smartphones is lower than similar models from other suppliers. This is due to the programming of such devices for a specific mobile operator. In Russia, such phones are not uncommon. What to do in this case? When buying a new device, you need to insert the SIM card of your operator and try to make a test call.
• Damaged SIM card slot. This is one of the most common factors in the problem under consideration, associated with the frequent change of SIM cards by the user, the phone falling into water, falling from a height onto a hard surface, and other stressful influences. Such cases may damage the card holder. In this case, the malfunction may not appear immediately, but will make itself felt over time. Also, the operation of the apparatus may be affected by a sudden change in temperature conditions and other physical parameters of operation.
• Wrong installation. A mobile phone or smartphone may stop seeing the SIM card after incorrectly installing the updated device software. What to do in this case? To restore the device's performance, you must install a factory modification of the operating shell or reflash it.
• The phone did not fully boot up. The more functional a mobile phone or smartphone is, the more RAM it has and the more powerful the processor, the more time it takes to load all the programs and services of the device after turning on the device. This may be the reason why the SIM card is detected after some time. It is necessary to wait until the phone is fully loaded and, perhaps, the SIM card will be detected.

The reason is the sim card

There are a number of reasons why the phone does not see the SIM card, related specifically to defects in the card itself.

• Subject to prolonged non-use of the SIM card or negative, it may be. Typically, such conditions are stipulated in the contract and they can be clarified with the company providing communication services.
• There are operators who follow the first paid action, be it a call or a text message sent.
• Incorrect trimming of a regular SIM card to a mini-SIM, or. Many users prefer to reduce the size of the SIM card with their own hands and at the same time spoil the contact pad of the chip. What to do to avoid this? You can use the services of specialists in mobile phone stores or pre-order a card of the right size from your operator.
• The SIM card may be damaged during use or when left outside the telephone. In addition, if you frequently remove and reinsert the SIM card into your phone, it may also fail.

» » Why the phone does not see the SIM card?

When turned on, the phone writes “insert a SIM card” - the situation is unpleasant, but in most cases it is fixable. Let's take a look at all the possible reasons why the phone does not see the SIM card. Below we will try to find out what the problem is - in the SIM card or directly on the phone and what to do in such a situation.

5 reasons why the phone does not see the SIM card

• SIM card not working

Despite the fact that a SIM card is a fairly reliable device, there are times when it stops working. Carefully remove the SIM card from the phone and carefully inspect for external damage. If the SIM card stopped working after you tried to cut it to a different format (micro or nano), the chip may have been hit and it has become unusable.

A great solution would be to first check the SIM card in a known-good phone.

If the SIM card looks good, gently wipe the contacts with a cloth soaked in alcohol and try to reinsert it into the phone. If it doesn't help, read on.

A defective SIM card will be replaced by the operator free of charge.

• Faulty SIM card holder

Another common reason why a smartphone does not see a SIM card is a loose SIM card holder connector. A malfunction is diagnosed by an external inspection of the holder for the integrity of the contacts. It is more difficult for those who do not have access to the holder, and these are almost all modern smartphones with a non-removable cover. In this case, you can not do without disassembling the phone. It is better to entrust it to specialists.

If the contacts of the holder are in place, it makes sense to try the next trick. Stick one or two strips of adhesive tape on the SIM card and carefully cut it around the perimeter. This will allow you to press the SIM card a little harder to the contacts and provide a more reliable connection.

• phone is locked

Almost all mobile operators have locked phones for sale, that is, phones that only work with SIM cards of one mobile network. So, if you insert a "non-native" SIM card into such a phone, it will not work.

In this case, the phone will need to be unlocked. This is not difficult to do, but this is a topic for a separate article.

• Phone settings

This solution to the problem applies only to owners of two-SIM devices. In some models, you can programmatically disable one of the SIM card slots.

You can check this by going to settings => SIM card manager and see if your phone has this option.

In push-button phones, it might look like this.

• Phone malfunction

If none of the methods helped, most likely the phone itself is faulty. In this case, only a service center specialist can help determine the reason why the phone does not see the SIM card.

Do not try to disassemble the phone yourself. If there is no experience, then with almost 100% certainty it will only get worse.

Many users are faced with a situation where their phones do not see SIM cards. There are several possible reasons for this problem, from card failure to problems in the smartphone itself, and the manufacturer does not matter here: the situation is equally typical for Apple, Samsung, Asus, Xiaomi, Sony and other popular brands.

Before diagnosing, you need to familiarize yourself with the main reasons why the phone does not see and does not recognize the SIM even after a reboot. The problem may be caused by the following:

• Card damage or expiration date;
• Violation of the integrity of the contacts in the connector;
• The gadget is flashed for a specific operator, and does not recognize other SIMs (most likely it was bought abroad);
• Unsuccessful flashing of the system;
• Sim card contacts pollution;
• Breakage of the card holder (re-soldering the contacts in the card slot will help).

Diagnostic instructions

When the user does not know what to do if the phone does not see the SIM card, he will need an instruction that allows him to perform the simplest diagnostics to detect the problem with his own hands:

1. We fix the SIM card. Even a slight shift in the slot, caused by shaking or falling, makes it impossible for the gadget to detect the card. This is especially true if the person himself cut it from a larger one, for example, he tried to make a micro-Sim.
2. We look at the plastic. If contamination is found on the side of the contacts, remove them with a damp cloth for equipment, observing the utmost care.
3. Pay attention to the slot. If the card holder loosens, the contact between the smartphone and the card disappears. You can put a piece of paper or slightly bend its part to increase the volume and create a more stable contact.

If the above methods did not help, you should put another SIM card in the slot: when the problem is in the phone, it will not be recognized either. Owners of dual-SIM smartphones just need to install the plastic in another slot and check if the network will be detected.

What to do if the problem is in the phone

The lack of a network, when the device stops recognizing the SIM card, can be caused by the following problems:

• Firmware for a specific operator. Here you can only reflash the gadget, because. any other manipulations will be useless.
• Slot damage. This is due to the fall of the gadget or the ingress of a large amount of moisture into it. For repair, it is recommended to contact the service center.
• Damage to operating system files. To restore the OS, you need to update Android by going to the settings. Rebooting will also help.
• Damage to the elements of the card capture reader. Only a specialist can fix the problem, because. this requires experience and ability to work with special equipment for repairs.

What to do if the reason is in the SIM card

When the smartphone has no visible damage, the problem may be in the SIM itself. Most often, they occur if the owner of the gadget has not used the SIM card for several months: some operators block numbers in such cases. You may have to visit the office of the company and write an application to unlock it, as well as pay money for restoration.

What to do if the SIM card stops working:

• If the nano-card has been cut off to turn into a "micro" unsuccessfully, it is worth checking it in another smartphone. If the assumption is confirmed, a reissue should be ordered from the operator.
• Sim contacts are clogged. In this case, it is recommended to gently clean them with a regular eraser to remove dust and other contaminants.
• Ask your service provider if the number is blocked. This is definitely worth doing after several months of not using this number.
• Sim needs to be activated. This happens after buying a new plastic. To activate, it is enough to replenish the balance or call a specific number: the procedure depends on the conditions of a particular operator.

Wrong Firmware: Consequences and Troubleshooting

Self-flashing the phone without the necessary skills and knowledge can lead to a malfunction of the entire system, as a result of which the smartphone will no longer recognize the SIM card and other additional accessories: headphones, MicroSD, charger, etc. To use communication services again, you will have to perform any action of your choice:

1. Restore the standard modification.
2. Take the device in for repair.
3. Revert settings.

If your phone does not see the SIM card, then first of all you need to try to rewind the events associated with the phone in your head in reverse order. It is worth paying attention to the possible causes of the problem with the SIM card. If the phone stopped seeing the card after a fall, then firmware and software updates will obviously not help. In the event that this happened without external influences, the reason may lie both in the deceased SIM card and in the bugs of the operating system. Let's understand everything in order.

No contact in sim card slot

Seeing on the screen the inscription “no SIM card” or “SIM card not inserted” on the smartphone screen, the first thing to do is to try to remove and insert the SIM card back. Perhaps the reason is simply that the contact in the SIM card slot has disappeared. This phenomenon is more often observed when using micro sim or nano sim through an adapter.

When extracting, you should look at the cleanliness of the contacts of both the SIM card itself and the slot. There may be some debris in the slot that interferes with the correct location of the card or interferes with contact. Therefore, it should be well blown into it. For a closed slot, you can use a vacuum cleaner, but a mouth will do.

If there is dirt on the contacts of the card itself, it is usually enough to rub it against a cloth, preferably a rough one, for example, wearing jeans. Also, a school eraser for erasing pens will do an excellent job. Although if you have poorly erasable traces on the contacts, then water probably got into the slot.

It also happens that the SIM card contact in the slot is lost due to insufficient pressing. In this case, it will help to lay a piece of paper folded several times, which should be positioned in such a way that when the phone cover is closed, it will squeeze the SIM card through the piece of paper.

Dead sim card

The problem may lie in the SIM card itself. It does not matter your phone does not see the SIM card of Beeline, MTS or anyone else. The validity of the SIM card is limited and it could simply expire. Well, or Simka was tired and died before the deadline for her. In any case, the second step of verification should be to check the SIM card itself.

To check, we put our SIM card into a friend’s phone, and his SIM card into ours. I think everything is clear here and without me it is clear. If a friend is not at hand, then you should go to the nearest office of your cellular company. There you will be checked and, if necessary, replaced.

Problems with iron

If your phone does not see the SIM card, but another phone sees it and sticking the SIM card into the slot does not help anymore, the problem probably lies in the hardware of the phone. For example, in a slot, as it was with me:

As you can see, one of the contacts fell off, which was on its last legs and was finally tired after the phone fell on the tiled floor.

With an open design of the SIM card slot, you should carefully inspect the slot for the presence of all contacts. It is also worth carefully inspecting the components around it. For a closed design, you can try to disassemble the phone and get to the slot. If you are not confident in your abilities, it is better to entrust the matter to a knowledgeable person.

If there are blackouts like soot around any part, then it burned out. There are also chips and cracks on the cases of microcircuits, indicating their death. But often the problem is invisible. There are microcircuits, popularly called “glasses” or “glasses”. Often this is not even a microcircuit, but a diode assembly in a glass case, but it doesn’t matter. The problem is that the contents of the glass are not soldered, but pressed, and with a strong mechanical impact, the contact can move out and disappear. In this case, only a replacement.

In some phone models, the slot is located or connected to a cable and you can replace it yourself with a new one. But in most, the slot is soldered directly to the board. In this case, it will not be possible to replace at home and you will have to go to the service center.

In addition to the slot, the problem may lie in the electronics. For example, problems in the communication module. Such things cannot be determined without special equipment.

Software part

There is a possibility that after a firmware or software update, the phone will no longer see the SIM card. There are several possible reasons for this:

• The update was crooked, for example, any necessary file was not installed - I'll have to reflash.
• Software incompatibility with your phone's hardware, especially with third-party firmware, such as Cinogen Mod and others. Sad but will have to try another version of the firmware.
• Errors in the program code or assembly files. There are copyright firmware collected by individuals. More often, such firmware is assembled for a specific model of a specific manufacturer. .

Very often, when updating or updating firmware, the old version of files and applications is not deleted. Instead, the new version of the files is installed on top. In this case, old errors migrate to the new firmware and give rise to additional problems. Therefore, when flashing, it is necessary to completely format the device