How to fix a Galaxy S9 keeps restarting and showing moisture detected warning [troubleshooting guide]

Today’s post handles three common issues that a lot of users encounter. Of special importance for us today is the case about a #GalaxyS9 that has a persistent random restarting and moisture detected issues. Together with two other related issues, we provide you the necessary steps that you can follow to tackle them head on. We hope that this short guide will help you address similar issues on your own Galaxy S9.

Problem #1: Galaxy S9 keeps restarting and showing moisture detected warning

Dear sir/madam. I am using Samsung Galaxy S9. My phone was working until few days back. My device is having a restart problem . My phone automatically restarts and shows the moisture warning message after it turns on. I cleaned the charging port, let it dry. it didn’t work. I was still having the same problem. I even reset the device thinking it was due to some application or any software that’s causing it. The problem was gone for 2 days but i still had the same restart problem. I removed my SD card, SIM card but neither of the tricks worked. i couldn’t find exact problem and solve it. PLEASE suggest me what the problem may be and what i should do. Thankyou! — Bikal Shrestha

Solution: Hi Bikal. Hardware problems tend to show symptoms consistently even after a factory reset so we don’t think the main reason for your issue is bad hardware. The most likely problem is either apps or content that you add to your device. We don’t know what apps you install but if the problem was gone for 2 days right after a factory reset, then you can rule out the possibility of hardware malfunction. Instead, try to focus on a possible bad app scenario or even a malware situation. Malware is one of the common reasons why problems persists even after a factory reset. That’s because users tend to re-install the same set of apps after a factory reset mistakenly thinking that the issue should not return. Malware in Android devices are usually spread via apps so if one of the apps you re-installed is a bad one, there’s no amount of factory reset that you can do to fix it. As long as you keep on reinstalling the same set of apps after a factory reset, the issue will return again and again.

The best thing that you can do right now is to run your S9 to safe mode and observe it. In this mode, all third party apps and services will be blocked, including the app that had infected your device. If your S9 works normally on safe mode and stops restarting on its own, that’s a clear sign of a bad app issue. Make sure to let your S9 run in safe mode long enough to allow you to notice if the problem occurs or not. We say you let it be on safe mode for at least 48 hours. You will still be able to use the internet on your pre-installed web browser, send and receive texts, and make and receive voice calls. If the problems you mention here won’t happen during the observation of 2 days, that’s an obvious indication of a bad app problem.

To boot your device to safe mode:

  1. Turn off your S9.
  2. With your S9 off 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.

If your S9 turns on to safe mode but not on normal mode, that’s a clear sign that one of your apps is indeed problematic. To know which app is causing a problem, 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 still refuses to power back on, repeat steps 1-4.

Problem #2:  Galaxy S9 randomly restarts for short durations of time

Hello. My Galaxy S9 that I purchased just over a week ago keeps turning off randomly for short durations of time. I have to manually turn it back on and when following your websites’ instructions and turning it on in safe mode, it is still turning off intermittently. I just switched from iPhone to this and feel pretty upset that I might have to deal with Samsung’s notoriously bad customer service department. Is there anything I can do short of a factory reset? I would prefer to not lose all of my settings and information I’ve been working for this past week to gain. Thanks for your time. — Walker Walker

Solution: Hi Walker. Any smartphone that restarts on its own may have a software or hardware problem. The restart symptom is just a sign that something’s wrong with it. In your case, you’ll have to do more troubleshooting steps than just boot the device to safe mode. If the issue is present even when it’s on safe mode, that doesn’t mean it can’t be a software issue. Nor does it necessarily mean that it’s a hardware issue either.

If you don’t want to do a factory reset right away, try to remember what you did differently before the issue started. Did you install a new app? Was there an app or system update that you downloaded? Did you drop the device? Was it water damaged? These are just some of the relevant questions that may cause a problem like this. If the previous action that you did immediately can be undone, make sure to do so. For example, if you recently rooted the device, try to unroot it and see how it works afterwards.

If you can’t figure out what may be the cause of the problem, try to see if resetting all its settings will help. It simulates similar effect to a factory reset without actually going through the hassle of clearing your personal data. Here’s how it’s done:

  1. Open Settings app.
  2. Tap General Management.
  3. Tap Reset.
  4. Tap Reset settings.
  5. Tap RESET SETTINGS button to confirm.

If that won’t fix the problem either, you need to factory reset your device. We know for a fact that an S9’s factory state software won’t have a random restart issue so if the problem remains after wiping your phone, that only means one thing — hardware malfunction.

To factory reset your S9:

  1. If still possible, make a backup of your personal 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.

Remember, factory reset is the final step in software troubleshooting. If your S9 continues to restart on its own, contact Samsung for repair or phone replacement.

Problem #3: Verizon Galaxy S9 stopped charging even after a factory reset

Like others who have written to you my Galaxy S9 suddenly stopped accepting a charge, even from the factory charger. After trying different cords, chargers and cleaning the contacts, I contacted Verizon.  They suggested a factory reset which I did. The problem persisted through the reset. The phone works fine but it wont take a charge. One Verizon tech support person let slip that this seems to be happening since Verizon’s last update!  So Verizon’s update has bricked my phone! Outrageous! Any ideas what to do other than buy a new phone? Thanks. — Resource3

Solution: Hi Resource3. We don’t work for Verizon and we don’t specifically keep track of Verizon devices having problems like the one you’re experiencing so we can’t say whether the representative who told you the issue started an update was saying the truth or not. What was said is not far-fetched though and there’s a possibility that it can happen. Apple did confirm a few months back that they intentionally slowed their older iPhones in order to prevent them from taxing old batteries and causing problems. A similar tactic can be used by Samsung or any carrier as well but we can’t categorically say if Verizon is doing it.

The interesting thing here though is that it won’t make sense at all since you have a Galaxy S9 and it’s pretty much new. There’s even no new replacement for it from Samsung so it’s not sensible for Verizon to intentionally rig their updates to cause the S9 to slow down or become problematic. That means your theory that Verizon may be forcing you to get a replacement may be a bit out of the question.

The thing is, we don’t think this is a software issue at all. If factory reset did not do anything, then there must be a hardware issue causing the trouble. It may be the charging port, battery, power management IC, or some general issue with the board. To know where the real issue lies, you need to let a professional examine the phone. We can’t tell you what it is by simply reading what you’re telling us. We suggest that you send the phone to Samsung Service Center so they can run some tests on it. If necessary, they will replace the phone for you.


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