Where to find diagnostic information as to why mobile data won't turn on I've had a Samsung Galaxy S3 for a little over a year now and not had too many problems with it. This afternoon, however, it's decided it won't connect to mobile data at all. I've had similar things on this and previous android phones, so I've tried:


making sure wifi isn't on
checking that mobile data is enabled (!)
checking the AP settings (these are actually locked down by my network provider - O2 UK)
turned on &amp; off airplane mode
restarted
powered off &amp; on
powered off, removed the battery and powered it back on


In all cases, I get no mobile data icon (so it's not even trying to connect from what I can tell) and I get no connectivity. Phone calls and wifi are working just fine.

Is there anywhere diagnostic information is kept around the status of the mobile data connection? If there's an error occurring, that would certainly be useful!

I did drop the phone a few days ago, but the mobile data has been working fine since then... but I guess it could still be related somehow. Even if that is the case and there's a hardware fault, the same thing applies - where is the diagnostic info?

I'm on the O2 UK stock image by the way - 4.1.2 / JZO54K.I9300XXEMC2
While in this case it turned out to be a carrier issue (and solved on the carrier's end, see this comment), in other cases one of the test menus might prove helpful. for a starter, you can find a lot of "secret codes" in this list for the SGS, together with a short explanation. But use them on your own risk :)