If your OnePlus phone starts to act funny, there's actually an easy way to check what's going on under the hood. You can do a brief check-up to see what's causing any problem before you head to the phone doctor. Just punch in *#808# into the dialer app to access a hidden menu with diagnostic options that you can use.

When the phone is set to be packaged and shipped, phone engineers make sure that the handset goes through a wide range of hardware diagnostic tests. This hardware test is designed to check for any potential flaws before the handset is shipped out. In the same way, you can run the tests to ascertain what is bugging your phone.

According to Phone Arena, the hidden diagnostic tests can check parts of the OnePlus 3 and 3T hardware. Parts that can be tested include screen components, LCD brightness and effects, hardware keys, vibration, sensors, GPS, and a great deal of other functionality. With the recent beta build of Oxygen OS update, the phone now have fixes for several important issues.

These phone issues include system rebooting when setting a wallpaper, night mode interruptions, Bluetooth and battery optimization, and many more fixes. However, if your phone persists with a problem that you suspects is a hardware fault, just dial in *#808# to see what's causing it.  There are a huge number of diagnostic tests available for the budget phone hailed as one of the best android phones today.

Per  XDA, you can access these tests on your OnePlus by typing “*#808#”. This will then open a page with a complete list of the diagnostic tests available including root checking and an option to erase all phone data. Type “*#80X#” to take you straight to individual tests based on the number you replaced X with.