How to fix Galaxy S9+ shuts down on its own if screen is off issue

Welcome to another troubleshooting article for the Galaxy S9+. Today’s post addresses a weird problem on this device. The issue is about an S9+ restarting by itself if screen is left turned off for some time. If you are one of the users affected by this problem, below are the steps to fix it.

Problem: Galaxy S9+ shuts down on its own if screen is off

Greetings, the issue I’m faced with is as followed; Everytime my Samsung Galaxy S9+ doesn’t have the screen on, it will turn off in about 1-3 minutes. Although if I’m playing music or I’m downloading something in the background it wont turn off. About half of the times it shuts off it will automatically restart, but if I dont unlock it or turn the screen on it will shut off and stay off. When I turn it back on all of my apps that were running in the background prior to it shutting off, are still running. I would greatly appreciate it if you could help me find a solution.

Solution: There’s a number of reasons why this problem occurs. To know what is causing it, follow the troubleshooting steps below.

Clear cache partition. The first thing that you can do in this case is to ensure that the cache partition is cleared. Doing so deletes the current system cache and forces the phone to create a new one. This is often effective in fixing problems related to bad system cache. There are all sorts of problems that can come up if the system cache becomes outdated.  

Here are the steps to clear the cache partition:

  1. Turn off the device.
  2. Press and hold the Volume Up key and the Bixby key, then press and hold the Power key.
  3. When the green Android logo displays, release all keys (‘Installing system update’ will show for about 30 – 60 seconds before showing the Android system recovery menu options).
  4. Press the Volume down key several times to highlight ‘wipe cache partition’.
  5. Press Power button to select.
  6. Press the Volume down key until ‘yes’ is highlighted and press the Power button.
  7. When the wipe cache partition is complete, “Reboot system now” is highlighted.

Install updates. Following the clear cache partition procedure, the next good thing to do is to install updates for both Android and apps. Some bugs are only fixed by implementing coding changes and updates sometimes do that. By default, your Galaxy S9+ should automatically check for updates on its own but if you changed this behavior, be sure to manually check for software updates under Settings.

For app updates, be sure to check for them in Google Play Store.

Safe mode. Sometimes, a third party app may interfere with Android and result to issues. To check if there’s an app the prevents the screen from working properly, you can observe the device while it’s running on safe mode. In this mode, all third party apps will be suspended. So, if the problem won’t occur in on safe mode, you can assume that one of the apps is behind it. To boot the phone to safe mode:

  1. Turn the device off.
  2. Press and hold the Power key past the model name screen.
  3. When “SAMSUNG” appears on the screen, release the Power key.
  4. Immediately after releasing the Power key, press and hold the Volume down key.
  5. Continue to hold the Volume down key until the device finishes restarting.
  6. Safe mode will display in the bottom left corner of the screen.
  7. Release the Volume down key when you see Safe Mode.

When safe mode is active on your device, only preinstalled apps can run. This means that any app that you added after initially setting up the phone, which what we refer to as third party apps, will be blocked. If one of them is the cause of the problem, the screen should work normally on safe mode and won’t turn off on its own.

If you suspect that an app is the underlying reason for the problem, you must use the process of elimination to identify it. Here’s how to do that:

  1. Boot to safe mode.
  2. Check for the problem.
  3. Once you’ve confirmed that a third party app is to blame, you can start uninstalling apps individually. We suggest that you begin with the most recent ones you added.
  4. After you uninstall an app, restart the phone to normal mode and check for the problem.
  5. If your S9+ is still problematic, repeat steps 1-4.

Uninstall apps. If you noticed that the screen problem occurs after adding an app, it makes sense to delete that app and see if it causes the issue.

If you don’t remember ever adding an app prior to noticing the problem, then you should do the safe mode procedure above and screen your apps properly. There is no list of bad apps in the Play Store so it falls on you to narrow down the possible culprit. Start removing apps that you haven’t used in the last two weeks. Such apps are probably not that significant for you lifestyle so you remove them from the device. You may have a game or productivity app that has not been used for a long time. Remove them and see if there’s any difference.

Reset all settings. This procedure is separate from the previous one as it covers all settings of your Android device and not just the apps. To do this, follow the steps below:

  1. From the Home screen, swipe up on an empty spot to open the Apps tray.
  2. Tap General Management > Reset settings.
  3. Tap Reset settings.
  4. If you have set up a PIN, enter it.
  5. Tap Reset settings. Once complete a confirmation window will appear.

Factory reset. Lastly, try to wipe your phone and return all software settings back to their defaults with a factory reset. This is an inevitable solution that you should do if all our suggestions above won’t help. To factory reset your S9+:

  1. Create a backup of your data.
  2. Turn off the device.
  3. Press and hold the Volume Up key and the Bixby key, then press and hold the Power key.
  4. When the green Android logo displays, release all keys (‘Installing system update’ will show for about 30 – 60 seconds before showing the Android system recovery menu options).
  5. Press the Volume down key several times to highlight ‘wipe data / factory reset’.
  6. Press Power button to select.
  7. Press the Volume down key until ‘Yes — delete all user data’ is highlighted.
  8. Press Power button to select and start the master reset.
  9. When the master reset is complete, ‘Reboot system now’ is highlighted.
  10. Press the Power key to restart the device.

Contact Samsung. If none of the solutions above won’t help, you should not hesitate to get help from Samsung. As an end user, there’s only so much that you can do. If a factory reset wont’ fix the problem, that means that it’s not a software issue. The most likely reason must be hardware-related so a full hardware diagnostics is required.


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