##634# Opens The Nokia Lumia 900 Diagnostic tool
I love hidden diagnostics. Lets you see what they play with and let’s you check to make sure things are operating ok. So if you have a Lumia just type in ##634## and a Diagnostic app will be added to your Lumia.
Accelerometer, ALS, audio loopback, camera, battery status, DTMF, gyroscope, hardware buttons, headset detection, LCD white, lights,life timer, magetometer, power source, proximity, speaker, touch and vibration.
You also have the option to run all the tests in one run
This was found in the AT&T forums from Pham. Thanks for the tip buddy- we appreciate it.