iPhone 16 Pro Max Liquid Detection

That’s the OP. I think he resolved his issue. The new poster is Rossruby.

I have seen instances where a tiny amount of lint in the charging port will result in a display of "water detected".

Very carefully, use a wooden toothpick and good flashlight to look into the port on the phone and clean out anything that might be there.

Note.....I would advise you to not use compressed air to try to clean out the port, as that might blow debris into the phone.

This issue persists, despite the phone not being near any water sources. It has been affecting my nephew’s phone, and I have tried using the original cable, as well as other cables, but the problem continues.

Water source can be high humidity or usage in low temperatures and then entering warm building. The condensation can cause temporary moisture detection. This is especially true in colder climates and more humid environments. I live in Florida near the gulf coast and in the summer, experience both hot and cold issues and high humidity.

Apple cables, in my experience, seem less prone to false positives, but if moisture is detected, patience rules the day.

Are you using Apple charger and Apple cable or third party items?

Non-Apple cables occasionally cause a false error. Is it a USB-C to USB-C cable? If so swap ends, just reverse cable.

Try the Apple cable that came with it or try reversing you off brand cable.

Yes it is an USB-C to USB-C cable, but I am using it only when I am traveling, because it is a longer one.

So, are you saying that the issue only occurs when you are using the "longer" Epico cable?