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 & off airplane mode
  • restarted
  • powered off & 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

  • 1
    There might be some test modes available, hidden behind some "secret code" entered via the dialer. You could check with this list for the SGS and see if you find a matching stick.
    – Izzy
    Commented Oct 3, 2013 at 23:10
  • Thanks for the pointer. In the end it appears to have been a carrier issue - I was unable to receive calls & texts as well (although I was able to make calls and send texts). Woke up this morning and it appears to be working again.
    – x3ja
    Commented Oct 4, 2013 at 9:39
  • Thanks for the feedback, x3ja! I tried to sum up everything in an answer (to make it obvious that your issue has a solution). Feel free to "accept" the answer to indicate it includes your remedy :)
    – Izzy
    Commented Oct 4, 2013 at 10:24

1 Answer 1


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 :)

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