The Mi 4 card has no signal, and the Mi mobile phone card is plugged in but there is no signal

Hi! It is recommended that you check it out by following the following methods:

Whether the SIM card is inserted correctly.

Whether the wrong SIM card is inserted, such as the standard version inserts the telecom SIM card, etc.

Go to Hardware Detection to see if the SIM card is working properly (enter * * on the dial screen). If the SIM status is normal, go to step 5, or if the status is unknown, go to step 4.

Try to replace a different SIM card, if the status is still unknown during hardware testing, it is recommended to go to the repair point for testing; If the detection status is normal, it is recommended to go to the carrier to replace a SIM card (the SIM card may be aging).

Whether the network type is correct and whether the carrier selects Automatic. (China Unicom selects 3G priority, mobile selects only 2G, and China Telecom selects automatic).

If the network type of the non-telecom mobile phone is CDMA automatic, you need to change the network type to the mobile phone information (**)."wcdma preferred"to solve the problem.

Whether there is no signal in the area. You need to check whether other mobile phones on the same network have signals.

Back up your data, flash to the latest system version and try again.

If the above methods still do not help you solve the problem, please go to your nearest repair point for repair inspection.

There is no signal on mobile phones because the signal will be affected by various factors such as terrain, landform, and tall buildings during the propagation process, and if you are in a relatively closed place, the signal will be affected. Here's how to deal with it:

Turn the phone back on and off and try again;

Swap the SIM card to a family member's or friend's phone and try again;

Check to see if other Unicom users around you have a signal;

Check whether your phone is set to airplane mode and check whether your phone is in arrears.

If your Xiaomi phone has a SIM card plugged in but doesn't have a letter orange scrambled number, there are several possible reasons and workarounds to try:

1.Check the SIM card slot: The card in the SIM card slot is inserted correctly. Try reinserting the SIM card to ensure good contact. Also check that the SIM card is properly installed on the card tray and make sure the card tray is fully inserted into the phone.

2.Check SIM Card Status and Balance: Make sure your SIM card is active and check that your account balance is sufficient. You can try inserting the SIM card into another phone to determine if it's an issue with the SIM card itself.

3.Network Settings Check: Go to your phone's settings menu, find the Network & Internet or Cellular options, select the carrier or SIM card, make sure you have selected the correct carrier and network type.

4.Shortcuts and airplane mode: Sometimes you mistakenly operate certain shortcuts or enable airplane mode on your phone, resulting in no signal shouting. Make sure your phone isn't in airplane mode, and check shortcut settings like the mobile data or signal disabling switch.

5.Network coverage and signal issues: Make sure you have adequate signal coverage in your location. If you're indoors, try getting closer to a window or a place with a good signal, and check for buildings, terrain, or other distractions that are blocking the signal.

6.Contact your carrier or after-sales support: If you still can't solve the problem after trying the above methods, it is recommended that you contact your carrier or after-sales support of your Xiaomi phone for further help and guidance.

Keep in mind that the above methods work in most cases, but the exact solution may vary depending on the phone model, carrier, location, and other factors. <>

1. Check whether the SIM card is inserted in the correct position, if so, you can reinsert the SIM card again;

2. Check whether the golden card area of the SIM card is obviously damaged, annihilated or scratched. If so, it can only be replaced;

3. If the SIM card is used for a long time or the SIM card is often unplugged, it will cause poor contact between the card and the mobile phone, at this time, you need to check the electrodes of the SIM and **, if it is not clean, you can use an anti-static cloth to clean it;

4. It may be that the signal is really bad, it is recommended to move to other places to try or try again later.

If the phone has no signal, no service, and does not read the SIM card, it is recommended to test it according to the following methods:

1.You can first open the phone's settings - about the phone, check whether the baseband version, IMEI, and serial number are unknown, if you find it unknown, it is recommended to send it for repair;

2.Go to "Settings--Network--Network Mode" and check whether the 2G 3G 4G setting mode matches the type of SIM card used;

3.Go to "Settings - Network - Network Operator", check Automatic, observe whether the service is restored, if there is no service recovery, restart to observe whether it is restored; If you recover after restarting, it may be caused by "baseband and firmware", and you can flash the firmware and baseband maintenance again.

4.Turn off the phone, pull out the SIM card slot, confirm whether the SIM card contact points are damaged or dirty, wipe it clean with a clean cotton cloth and insert the phone again to confirm whether it is restored;

5.Replace SIM card test.

Note: If the fault persists, it is recommended to send it for repair.

Please ask which version of your phone is and which carrier's network you are using.

1. If it is not the reason for the poor signal of the environment you are in, please open the settings Mobile Network Network Type Selection Choose to use only 2G network and try to see if it is normal.

2, if it doesn't work, remove the SIM card, reinstall it again, try to see if it's normal, 3, still doesn't work, it is recommended that you change the SIM card to try it.

4. If it still doesn't work, please take your mobile phone to a Xiaomi authorized repair point near you or Xiaomi Home for testing.

Authorized repair outlets address and ** inquiry.

Mi Home address and ** query.

Mi Home is open from Tuesday to Sunday, from 10 a.m. to 6 p.m.

**The after-sales principle of Xiaomi mobile phones and Redmi mobile phones and Xiaomi tablets is the failure of non-human damage: return within seven days, replacement within fifteen days, and within the one-year warranty period, non-human damage is completely free.

I hope the above reply can be helpful to you.