Launch the phone app and open the keypad. Tap the following keys: #0#. A diagnostic screen pops up with buttons for a variety of tests. Tapping the buttons for Red, Green, or Blue paints the screen in that color to make sure the pixels are working properly.

How do I run mobile diagnostics?

Here are the two main codes usable on most Android devices:

1. *#0*# hidden diagnostics menu: Some Android phones come with a full diagnostics menu. …
2. *#*#4636#*#* usage information menu: This menu will show up on more devices than the hidden diagnostics menu, but the information shared will be different between devices.

How do I run a diagnostic on my Samsung phone?

Accessing the Secret Diagnostic Menu

To get the ball rolling, simply open your Samsung’s phone app. From there, enter *#0*# using the dial pad, and the phone will immediately go into its secret diagnostic mode.