Dialing *#0*# brings up the General Test mode on the Samsung Galaxy S23. It's a hidden diagnostic tool that you can use to troubleshoot and test various hardware components and features of the device.

nF: Water Is Not Filling. If the washer takes more than 40 minutes to fill, or if the water level doesn't change after six minutes, the nF code will appear.

TechNastic published a list of other Samsung secret codes recently. You can use these codes on almost all devices from the S5 to the S20 line, as well as the Note 4 to Not 20, Galaxy A to M, or ...