Ursprünglicher Beitrag von: Niadruoj ,
My phone (Galaxy S4) displayed the same message although the temperature was close to 30°C (86°F). In addition, the icon "charging" appeared although the device was not connected to a charger. I opened it, discovered some traces of water (realizing that the device was actually exposed to some water earlier during the day), carefully wiped water droplets and let it dry overnight. On the next morning, the problem was fixed.