Lately my s9 plus has been saying weak charging detected and I have no Idea why it's doing that.. also when I use a car charger it starts to beeped and say moister has been detected but have never gotten my phone in the water, any idea why its doing that?
Have seen few reports of this...
Have you looked at the charging port on the phone and the cable? No lint, no dust?
Turn device off, then back on
Flip the connector around and plug it in, see what happens.