Xiaomi phone doesn't see SIM-map: step-by-step action plan

The situation when a modern smartphone stops recognizing a SIM card, always takes you by surprise, especially if you need urgent communication. Instead of the usual “flying” of the signal on the screen Xiaomi or Redmi appears crossed-out SIM or message about its absence. The user immediately begins to panic, believing that the problem lies in a complex hardware failure or failure of the motherboard.

But in most cases, the reason is much deeper and simpler: it can be an oxidized contact, a software glitch of the MIUI or HyperOS operating system, as well as the banal wear of the plastic base of the SIM card. In 80% of cases, the problem is solved by software resetting network settings or physical cleaning of contacts without visiting the service center. Before carrying the device for repair, you need to exclude all possible software conflicts.

Next, we'll look at a detailed algorithm that can help restore communication, going from simple reboots to complex manipulations of the engineering menu and hardware, and it's important to follow each step consistently to accurately diagnose the source of the malfunction.

Primary diagnosis and rapid reboot

The first thing to do when a problem is detected is to perform a banal, but often effective, system restart. MIUI It can accumulate temporary errors in the radio module that is responsible for communication, restarting the device clears the RAM and forcibly restarts all system services, including those responsible for detection. SIM-map.

If a simple reboot didn't work, try removing the SIM card and inserting it again, which allows you to physically update the contact between the metal plates of the card and the phone's reader, and it often happens that the card just shifts slightly in the tray due to vibrations or falls.

Pay attention to the state of the SIM card itself when removed, it should not be deep scratches, chipped or corrosion marks. If you see oxidation on the contacts, gently wipe them with a soft dry cloth or a wiper, but do not use alcohol or aggressive liquids that can damage the plastic base.

⚠️ Warning: Before removing the tray, make sure the device is turned off or use a hot replacement if the model supports such a feature, but it is safer to work with the screen off to avoid short circuits.

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Try inserting the SIM card into another slot (SIM 1 or SIM 2). Often one of the slots can work correctly, which temporarily solves the communication problem.

Checking the physical condition of the tray and map

Physical damage is the second most common reason why Xiaomi doesn't see the SIM card. The SIM card tray is a mechanical element that is constantly exposed. Over time, the metal contacts inside the tray can become clogged or oxidized, no longer pressing the card tightly against the contact group.

It's also worth checking if the SIM card is cut correctly. If you've recently changed operator or cropped the card by hand, it may be non-standard size or chipped around the edges. In a Redmi and Poco tray, tolerances can be minimal, and even millimeter deviation leads to no contact.

Let’s look at the main signs of physical problems in the table below:

If a visual inspection reveals serious damage to the SIM card itself, the best solution is to go to the operator’s salon for a free replacement, and the new card will provide a stable signal and support for modern encryption standards.

Network settings and operator selection

Often the problem is not hardware, but software settings. Xiaomi smartphones have a manual or automatic network selection feature, and if the phone can’t find the network for a long time, maybe priorities have gone wrong or frequency conflicts have occurred.

Go to the Settings menu → SIM-You can pick up the problem SIM card and find the "Network Type" option. 5G/4G/3G/2G Only 4G or even just 2G. If the regime 2G The network has appeared, so the problem is in the coverage. 4G/5G your operator in the area or in the frequency settings.

Also critical is operator choice: In the SIM card settings menu, find Operators or Network Selection. Turn off automatic selection and wait for the phone to scan the airwaves. If your carrier appears on the list, force it.

Sometimes it helps to reset your mobile network to factory settings, which won't delete your personal data, photos or contacts, but will return your communication settings to the original state. Way to run: Settings → Connection and Sharing → Reset Wi-Fi, mobile Internet and Bluetooth.

Resetting the settings of the APN access point

If the phone sees a SIM card but the internet is down or a connection error is constantly flying out, the problem may lie in the settings of the APN hotspot. Operators periodically change the parameters of the gateways, and the old settings in the phone may conflict with the new network requirements.

To correct the situation, go to Settings → SIM-maps and mobile networks → (Select a SIM card) → Access points (APN). In the list that opens, click Reset (usually at the bottom of the screen or in a three-dot menu). Once reset, the phone will download the current settings directly from the SIM card or from the internal database.

If automatic reset didn't work, you can create a new access point manually, and the data to fill in (name, APN, login, password) can be found on your mobile operator's official website, and be careful when you type in: even one extra letter in the APN field will lead to no Internet connection.

⚠️ Note: When creating an access point manually, do not change the authorization type and protocols (IPv4/IPv6), If you are not sure if they are correct, leave the default values (usually) PAP or CHAP).

Update and reset to factory settings

Software bugs in the shell MIUI HyperOS is a common occurrence, and developers regularly release updates that fix radio module errors. → If you have a new version of the system, you should install it.

In cases where the problem has occurred after a recent update, the situation may be reversed: the new firmware contains errors, then you should try to roll back to the previous version or wait for the next patch, and you can also try to reset the network settings, as mentioned earlier, but a more radical method is a complete reset.

A full Hard Reset removes all data from the device, so make sure to back up. Once reset, the phone goes back out of the box. If the SIM card is undecided after reset and without installing third-party apps, the probability of hardware failure is up to 99%.

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Complete reset is an extreme measure of software diagnostics, and if it doesn't work, further software manipulation is pointless.

Hardware malfunctions and repairs

When software methods are exhausted, you have to talk about hardware. The most common hardware reason is the failure of the SIM card reader itself (SIM-It's a low-cost module that is soldered to a board or connected via a plume. It takes about a week to replace it. 30-60 minutes at the service center.

A more serious problem is the damage to the tracks on the motherboard or the failure of the power controller that distributes the voltage to the communication module, which can occur after a fall, moisture or a surge in voltage during charging, in which cases complex soldering and diagnostics on professional equipment are required.

Also worth mentioning is the possibility of damage to the antenna module, which, although this often affects the signal level, in some cases, the antenna cable can lead to the complete disappearance of the network, and the antenna is diagnosed using a tester and visual inspection of the internal components.

⚠️ Note: Self-opening of Xiaomi smartphone can lead to loss of warranty.If the device is warranty, contact an authorized service center.

You can use a special engineering mode to diagnose it. Dial ##4636## in the call app. In the phone information menu, look at the signal status. If it says "Disconnected" when you inserted the card, and resetting the settings didn't help, it's probably a physical problem.

Frequent Questions and Answers (FAQ)