I've looked through the other thread on this topic and there does not seem to be any indication that anyone has figured out what is actually causing the warning to trigger without the port actually being wet - there also doesn't seem to be an actual fix to the problem. I have been having this issue for quite a while and only recently figured out what is causing the issue in my case.
If the power being sent to the phone is cut off WHILE THE USB IS PLUGGED INTO THE CHARGING PORT, this triggers a "moisture detected" warning. If I accidentally unplug the charging block from the wall while the USB side is still plugged into the phone, the phone for some reason thinks it's wet and the alarm will go off. If I plug my phone into my car as soon as I start the engine, the alarm will go off - I need to wait at least twenty seconds after starting my car before plugging it in. I believe it is a software issue, where it is interpreting immediate surges in power as an indication that the charging port is wet, even if it is not wet.
The solution I have found is to plug the phone back in and while the alarm is going off, hold down the power button until it prompts you to power off or restart. Restart the phone while it is still plugged in with alarm going off. This ALWAYS fixes the problem in my case. It may not work the first attempt, but in every case it's worked within 5 restarts of the phone, all while leaving the phone plugged in. Unfortunately, this is not a permanent fix. The scenarios described above still trigger a false warning. But everytime it occurs, restarting the phone while it is plugged in always fixes the issue in my case.
Has anyone else had similar issues/solutions?
This is an incredibly annoying issue and should be addressed through a software update.
I totally understand your frustration, and how annoying it can be. With the s9, it typically has to do with a fingerprint sensor that causes that, even though the fingerprint sensor is working. I suggest taking it into a local Samsung store when they reopen or a Samsung certified repair store to further diagnose the phone. This way you can stop having that annoying popup message.
-Feel free to contact 1800SAMSUNG for support as well
I'm sorry and completely understand your frustration. If you've exhauseted all trouble shooting methods I suggest contacting support. They can provide you with the steps for a mail-in repair or help you set an appoint with an authorized Samsung Repair Center once they re-open. In the mean time, if the phone isn't charing on the cable, you can still use a wireless charging pad.
Please remember to back up all your data if the mail-in repair is needed.
Hope this helps!
I had the same problem and did the followng steps and it worked for me.
1. go to storage settings.
2. in usb settings - clear the cache.
3. Restart phone.
4. When the phone restarts go to battery settings.
5. Disable fast charge and then switch it back on.
6. Put the phone back on charge.
Sometimes there are things in the CACHE that creates this warning. Good luck and let me know if you have sucess.