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2. Reasons for the phone recognizing SIM but having no signal
- Due to network issues: check by calling friends or family using the same network to see if there is a signal. If theirs is working and yours is not, it's likely a network problem.
- Due to a damaged SIM: to check, insert the SIM card into another phone. If there is still no signal, the SIM may be damaged, leading to this issue.
- Due to your location: if you are in an area with weak signal, such as hills, rural areas, islands, or places with many devices sharing the same signal tower, your phone signal may also be weak or nonexistent.
- Phone in airplane mode: many people habitually leave their phones in airplane mode when sleeping or while on a plane. If airplane mode is not turned off, the phone will have no signal even with a SIM card inserted.
- Using a locked device: phones imported from abroad are often locked. Therefore, they may not be compatible with the network, resulting in a signal loss.
- Hardware issues: Hardware damage can also cause a phone to have no signal. Dial *#06# to check if the IMEI is displayed. If not, the hardware may be faulty.
- Software issues: Problems during device upgrades, software installations, or application errors can lead to the phone not recognizing the SIM card.
3. 8 solutions to fix the issue of a phone recognizing SIM but having no signal on an Android phone
3.1. Restart the device
This is a simple and commonly applied solution when the phone loses signal. This solution provides quick results. All applications and programs running before will be closed, and the phone will start searching for a signal again. However, you should only use this troubleshooting method when the phone does not frequently experience signal loss, as it is only a temporary solution for mild signal issues.
3.2. Enable/disable airplane mode
If your Android phone recognizes SIM but has no signal due to being in airplane mode, simply turn off this mode and wait for about 10-20 seconds for the phone to regain signal. Additionally, if the phone is not in airplane mode but still has no signal, you can turn on airplane mode. After about 30 seconds, turn it off. At this point, the phone will initiate a search and may regain the signal.
3.3. Check the SIM card again
Sometimes, signal loss may be caused by users incorrectly inserting the SIM card. In such cases, turn off the phone, then check the SIM card to see if it is inserted correctly.
3.4. Enable Mobile Network Automatically
This is the automatic signal search mode in the design of all Android devices. To choose this mode, follow these steps:
- Go to Settings
- Select More Network
- Select Mobile Network
- Next, choose Network Operators and select Select Automatically
At this point, the device will automatically search for a signal and address the issue effortlessly.
3.5. Choose the correct frequency band
Android phones losing signal may result from selecting the wrong signal frequency band. To fix this, you can follow these steps:
- On your keypad, dial: *#*#4636#*#* and press Call, then wait for the result
- The device adjustment screen will appear; access it and select Phone/device information
- Press Run Ping test and choose GSM Auto/PRL from the displayed list
- Select Turn off Radio
After completing these steps, exit and restart the device. Then, check if the phone has signal.
3.6. Software update
If you have tried the above methods and still cannot resolve the issue, proceed to update the system software. This will help address some lingering errors in the device, enhancing overall performance.
To update the system software, follow these steps:
- Step 1: Go to Settings → select About Device or About Phone
- Step 2: choose Check for Update
- Step 3: Select download and install the latest version
After updating the software, the phone will automatically restart. At that point, check if the phone has a signal.
3.7. Resolve from IMEI
Some phones may lose IMEI without your knowledge, leading to signal loss. To ensure if your phone has lost IMEI, dial *#06# on the keypad and press Call. If the phone still has IMEI, it will appear on the screen. If the screen shows Null or Unknown, your phone has lost IMEI.
To retrieve the IMEI, dial *#*#197328640#*#* on the keypad and press Call. If nothing is displayed, dial the code again *#197328640# → Call. If correct, the command mode screen will appear. Continue to select Field Test Mode. If Field Test Mode is ON, turn it OFF. Next, choose Menu, and the IMEI number will reappear. Finally, restart the phone and check if it has a signal.
3.8. Restore to factory settings
This is a method to bring the device back to its original factory settings. Note that when restoring to factory settings, all data will be lost. You should back up important data before proceeding. Then follow these steps:
- Step 1: Go to Settings → Select Backup And Reset
- Step 2: Press Factory Reset
The device will restore to factory settings, deleting user data and previous settings. After the reset is complete, restart the phone and check if the signal has returned.
4. 7 ways to fix the issue of a phone recognizing SIM but having no signal on an iPhone
Regardless of the make and model, any modern phone is susceptible to the issue of recognizing SIM but having no signal, even an iPhone. To address this problem, consider these 7 methods below.
4.1. Move to an area with stronger signal
When you are in tall, enclosed buildings, elevators, or hilly areas, the iPhone signal may be weak or nonexistent. The solution at this point is to move out of that area and go to a location with a stronger signal coverage. You don't need to intervene inside the phone at this time.
4.2. Damaged SIM card
If you are in an area with good signal coverage and still experiencing the issue of iPhone recognizing SIM but having no signal, the cause may also originate from the SIM card. Although the possibility of a damaged SIM is small, it is not unheard of.
First, use 90% alcohol to clean the SIM card's metal surface, then use a dry cloth to wipe it clean and reinsert it for testing, or try it in another device. If both phones still have no signal, the main cause is the SIM card. Visit the nearest service point of your network provider to get a replacement SIM card.
4.3. Turn off airplane mode
If the iPhone is losing signal due to being in airplane mode, simply turn off this mode. Alternatively, you can use airplane mode to resolve the issue of the phone recognizing SIM but having no signal. Activate airplane mode, wait for about 30 seconds, and then turn it off. At this point, the phone will perform a signal search again.
4.4. Use a SIM adapter
You need to use a SIM adapter to address the issue of no signal when using a locked iPhone. Locked phones are imported from abroad and are not compatible with the network system in Vietnam, leading to issues. The SIM adapter is inserted with the SIM you are using to unlock the network for the iPhone.
4.5. Reset network services
This means resetting the phone's network settings to the factory state. During usage, opening multiple applications can overload the phone, causing application conflicts and signal loss. At this point, you should reset the phone to give it a fresh start.
To perform this, go to Settings → General → Reset → Reset network settings. Performing these steps will help reset the network settings to the default without losing data.
4.6. Restart the device
If your iPhone doesn't lose data when facing no signal, you can use the method of restarting the phone. Turn off the power, wait for a while, and then turn it back on. For phones experiencing frequent signal issues, this method should be avoided.
4.7. Restore to factory settings
If you have reset the network settings as instructed above and still experience the issue of the phone recognizing SIM but having no signal, you should either upgrade the software or restore the entire device. This will result in data loss, so make sure to back up your data to another device before proceeding with the restore.
To perform this, go to Settings → General → Reset → Erase All Content and Settings.
Hope these insights will assist you in resolving the issue of the phone recognizing SIM but having no signal on your device. Best of luck to all of you!
