Location using mobile data

[Leo761]

My mobile data is turned off and I am connected to my WiFi. Every time any app is using location my cellphone connects for a second to the network and uses mobile data, although mobile data is still turned off. As I use a prepaid SIM card I have to pay for 15min data use, even if my phone connects just for a second. Either I can turn off location or delete the APN to solve the problem for now but it is not a real solution. Anyone has an idea?

[Uliwooly]

Settings > location > what do you have it set as ?

[Leo761]

High accuracy, but I tried already device only GPS, and I still have the same issue.

[Uliwooly]

You have answered your own question 

High accuracy > Use GPS, Wi-Fi, Bluetooth, or cellular networks to determine location

[Leo761]

I appreciate your answer, but as I said, even if I use GPS only, it still connects to the network for a second. If I turn Location totally off, it will not connect. As soon as I turn it on, no matter what configuration, it will connect, and that is not how it is supposed to be.

[Rickard · Accepted solution]

What you can try instead of deleting the APN is to edit it and check the APN-type. If the APN-type contains "supl", remove this and save the APN.

The GPS in the phone supports assisted start and can use the mobile network to get your location faster than a normal GPS. Removing "supl" may prevent it from doing that.

[Leo761]

Thanks a lot for the tip. I deleted supl in the settings of the APN-type and it seems to be working now. When I open Google Maps and use the GPS it is not using any mobile data anymore when I am connected to my WiFi.
I will further observe.
So this is all a software issue. I'm just curious. Will Sony address this in future software updates?

[Leo761]

I still don't understand how the GPS can overrule the mobile data off setting. Thanks anyway again

[Rickard]

Glad to hear that

When you turn off mobile data in the phone, you only disable "internet" over mobile data. Some services that depends on the mobile network like MMS and the AGPS can still use the mobile network if you have an APN with an APN-type telling Android that's what the APN is for. So it's designed to work in this way.

[Leo761]

Thanks for the explanation. My old xperia zr has default, supl, a-gps as it's APN-TYPE. I never experienced this issues with the ZR. Same provider. What is the difference?