How to fix Galaxy S9 random restart: works for minutes before restarting on its own

Hello and welcome to another #GalaxyS9 troubleshooting article for the day. In this short post, we bring you another classic case of random restart issue. As usual, we also provide the solutions you can try on your end to fix it. Just remember, random restart issue has a hardware side as well. If all software solutions fail, you can assume bad hardware is causing the trouble.

Today’s Problem: How to fix Galaxy S9 random restart: works for minutes before restarting on its own

Hello. my Samsung S9 keeps glitching… after it dies my Samsung turns on and then when I try using it it wont let me. It would turn on and then a couple minutes goes by and then goes off again. It’ll do this for more than an hour and then work like nothing happened. Is it possible a drink could’ve gotten into it and it f’ed it up??

Solution: The Galaxy S9 is a water-resistant device so it can’t be damaged by casual liquid or water splashes. The water-resistance protection in your device though can be compromised if there’s a physical break in the phone, like after dropping it, or if there’s a factory defect without you knowing it. Galaxy S9 devices with defective water resistance from factory is very rare and does not always result to problems unless a user swims or dives with the device. If you happen to dampen the device with liquid or drink before, all you have to do is to simply rinse it thoroughly with tap water to remove any residue. Once you dry the device properly, you can use it without any issues. So, we don’t think the reason for your main problem is due to water or liquid damage at all but probably a software or a deeper hardware malfunction.

To troubleshoot the device, follow our suggestions below.

Use another charging accessories

The first step is to ensure that the battery is charged properly. If it does not get the right amount of power before you turn the phone on, or if there’s an external issue charging wise, it may not work properly whenever it’s stressed by normal use. To see if there’s any issue with the current charging cable and adapter, try charging your phone with another set of accessories. If you can’t readily find an official S9 charging cable and adapter, you can do these things:

  • borrow them from a friend
  • use ones from your local Samsung store
  • use a wireless charger

Remember, your goal here is to check for the possibility of a charging cable or adapter issue. If nothing changes after doing any of the suggestions above, proceed to the rest of steps below.

Clear cache partition

If you can manage it, the next step that you want to do is to boot the phone to Recovery Mode and wipe its cache partition. This is one of the partitions in your phone’s storage device that keeps the system cache. Sometimes, updates and app installations cause this cache to get corrupted, in turn, causing all sorts of problems. To see if you have a cache problem, follow the steps below to clear the cache partition:

Turn off the device. This is important. If you can’t turn it off, you’ll never be able to boot to Recovery Mode. If you are not able to shut the device off regularly via the Power button, wait until the phone’s battery is drained. Then, charge the phone for 30 minutes before booting to Recovery Mode.

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

Re-calibrate battery

Should nothing change after the system cache has been refreshed, the next step in your troubleshooting ladder is to recalibrate Android and the battery. Sometimes, Android may get inaccurate battery readings if the device is left running for a long time. It’s advised to regularly calibrate the battery to avoid having power problems.

  1. Drain the battery completely. This means using your device until it powers down by its own and the battery level reads 0%.
  2. Charge the phone until it reaches 100%. Be sure to use original charging equipment for your device and let it charge up completely. Do not unplug your device for at least two more hours and also don’t use it while charging.
  3. After the elapsed time, unplug your device.
  4. Restart the device.
  5. Use your phone until it completely runs out of power again.
  6. Repeat steps 1-5.

Observe in safe mode

One of the possible reasons for your problem may be an inefficient app, or even app-based malware. This is also one of the common reasons for a lot of Android issues. To check, restart the phone to safe mode and observe. If your S9 works normally and won’t reboot on its own, then one of your apps must be to blame.

Here are the steps on how to boot 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.
  8. Observe the phone while it’s on safe mode for at least 24 hours.

If the issue won’t happen when your S9 is on safe mode, bad third party app is behind it.To identify which of your apps is causing the trouble, you should boot the phone back to safe mode and follow these steps:

  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.

Factory reset

In majority of cases similar to yours, factory reset is the ultimate test to see if the cause is a software bug or not. It’s also the one way to know whether the issue is fixable on an end user’s level. Needless to say, you want to factory reset your S9 should all our suggestions above won’t help.

Factory reset wipes all user data so be sure to back your files up before doing it. We assume you create a copy of your irreplaceable data regularly but if you haven’t, try to back them up to a computer instead of uploading them to a cloud. Not only is a backup to a computer faster but it can also ensure that your S9 is being charged while it’s moving files. For a more efficient backup job, try to use Samsung’s own Smart Switch.

To factory reset your S9:

  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 data / factory reset’.
  5. Press Power button to select.
  6. Press the Volume down key until ‘Yes — delete all user data’ is highlighted.
  7. Press Power button to select and start the master reset.
  8. When the master reset is complete, ‘Reboot system now’ is highlighted.
  9. Press the Power key to restart the device.

Get professional help

As an end user, there’s only so much that you can do to troubleshoot this issue. If your phone continues to show the same problem after a factory reset, this means the problem is probably deeper. It can be a bad battery or any other logic board issue. To know where the problem lies, a technician must conduct a full hardware diagnostics. Only then can Samsung advise you whether or not the phone can be repaired or if it needs replacement.

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Harvey is keen with mobile technology and loves writing about all things mobile. He is passionate in helping technology-challenged people by finding resolution to their issues.

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