What to do if Galaxy S9 won’t charge when the screen turns off [troubleshooting guide]

Hello and welcome to another #GalaxyS9 troubleshooting page. This post will try to answer 2 issues reported for this device over the last few days. For the first case, we don’t have enough information yet whether or not it’s pervasive so we’ll continue to monitor it. Our main topic though centers around what you can do when your S9 stops charging the moment the screen turns off. We’ve seen this issue occur in both Samsung and non-Samsung devices in the past so it’s probably affecting a number of users. We hope we are of help to them.

Problem #1: Galaxy S9 turns off by itself when it’s inactive

Hello. I’ve had my S9 since release and this past week it has started to reboot/turn off by itself. I ran all of your sugested trouble shooting (safe mode, clear cache, factory reset) and the issue still persists. The part I find most strange is it will only happen when the phone is inactive. Never when I’m using it or even when I’m streaming music to my car, only when it is lock and mostly when it is in my pocket or turned face down. Stranger even, it was turned off for 12 hours over the weekend and I did not have the issue the whole next day until i fully charged it overnight. I woke up to it shut off. Have you heard of this issue before? Is this just something I need to contact Samsung to fix? I have an unlocked S9 purchased through Samsung and I have been using a Belkin charger. Thank you in advance. — Kevin

Solution: Hi Kevin. No, we haven’t heard of this issue before so we don’t have any idea how to best address it. Since all the usual software solutions that you can do have no effect whatsoever, this problem must be beyond your ability to fix. We are yet to hear the same or similar issue from other users so we it may be an isolated case. There may be a motherboard issue causing power management to behave erratically. Even Samsung will have a hard time knowing where the problem lies so you’ll most probably end up with a phone replacement if you’ll tap Samsung warranty on this one. We strongly recommend that you talk to Samsung about this though as they have the means to figure out whether or not this issue is isolated or not.

Problem #2: Galaxy S9 won’t charge when the screen turns off

Hi. I have a problem with my S9 charging. it will charge when the screen is on just fine, but the moment the screen switches off, I get the little animation to say that the phone is charging, and if I leave it on the lock screen it just stays on the same percent, with charging switching on and off. It’s gotten to the point where the phone will completely discharge itself and and I won’t be able to turn it on to start charging again. it’s a vicious cycle and I’m getting sick of it. I hope you can help me. — Liam.farrell.stpaulsnz

Solution: Hi Liam. Like all Android problems, yours might be caused by a software glitch, a bad app, or a hardware error. There’s a short list of things that you can try so kindly go over them below.

Recalibrate the battery and Operating System

Android may sometimes lose track of actual battery readings. This usually happens if your phone has been up for far too long (like a few months). The longer Android runs, the higher the chance that it may not be able to get accurate battery stats, which can then result to power issues or random reboots. To minimize this situation from developing, you want to ensure that you recalibrate the battery and OS from time to time. Here’s how to do that:

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. Perform a warm restart by holding the Power and Home buttons simultaneously until the startup logo appears.
5. Use your phone until it completely runs out of power again.
6. Repeat steps 1-5.

Clear the cache partition

If nothing happens after the calibration, the next step for you is to wipe the cache partition. This is to ensure that the system cache is refreshed.

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 Android logo displays, release all three keys.
4. An ‘Installing system update’ message will show for 30 – 60 seconds before the Android system recovery menu options appear.
5. Press the Volume down key several times to highlight wipe cache partition.
6. Press Power key to select.
7. Press the Volume down key to highlight yes, them and press the Power key to select.
8. When the wipe cache partition is complete, Reboot system now is highlighted.
9. Press the Power key to restart the device.

Observe your phone on Safe Mode

There’s a chance that a bad app may be to blame for your troubles so the next step is to run your S9 to Safe Mode. In this mode, only pre-installed apps will be permitted to run. So, if your phone works normally on safe mode but not when you boot it back to normal mode, that’s an obvious sign of a bad app problem.

To restart your S9 to safe mode:

1. Turn off your S9. If you can’t turn it off normally, let the phone drain its battery until it turns itself off.
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.
8. Check for the problem by allowing your phone to work on this mode for a few hours.

To know which app is problematic:

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 wifi is still problematic, repeat steps 1-4.

Factory reset

Finally, you want to wipe the phone and return all its software settings back to their defaults. This is accomplished by doing a factory reset. If you haven’t tried it yet, here’s how to do it:

1. Turn off your Samsung Galaxy Note 5 completely.
2. Press and hold the Volume Up and the Home buttons first, and then press and hold the Power key.
3. Keep the three buttons pressed and when ‘Samsung Galaxy Note5’ shows, release the Power key but continue holding the other two.
4. Once the Android logo shows, release both the Volume Up and Home buttons.
5. The notice ‘Installing system update’ will show on the screen for 30 to 60 seconds before the Android system recovery screen is shown with its options.
6. Use the Volume Down key to highlight the option ‘Yes — delete all user data’ and press the Power key to select it.
7. When the process is complete, use the Volume Down key to highlight the option ‘Reboot system now’ and hit the Power key to restart the phone.
8. The reboot may take a little longer to complete but don’t worry and wait for the device to become active.
9. Let your Note5 run for an hour and check for the problem.

Remember, factory reset will erase all data on your phone so be sure to back them up ahead of time.

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