Sony Xperia T L30p cellular data issues I have a Sony Xperia T L30p. When mobile data is switched on it works fine, but, when the network coverage is poor and the signal gets lost the cell phone switches off by itself. Then, I must switch on the phone by myself but most of the times it just restarts my phone to the pin number login. I repeat that happens only when the cellular data is on and only when the signal coverage is zero.

Thanks in advance.
I suggest that you try to run a software reinstall using SUS. Follow
this link for reference.

If the problem still remains you should contact your local support team, to have the phone examined and fixed at an repair center. Use this link to locate service station.