In Some of the Android phones i observed that if 3G or HSUPA signal is weak, then these phone will get switched to 2G mode automatically.
Though we set preferred network type as 3G, they wont connect to 3G always. Only in some specific location we get 3G. If the signal strength gets one stick down also it get automatically switches to 2G. Browsing speed of 3G is always good compare to 2G. Some of the mobile phone like Samsung works well in this case, but few phones like Moto G, wont work well.
I faced similar issue in my Motorola 2nd gen phone, looks like 3rd gen is also having same issue. Follow these simple steps to fix this problem, this will ensure phone will be in 3G or WCDMA mode always.
- Better insert the SIM which connects to 3G in slot 1 and other one in slot 2
- Connect to internet through SIM 1, you will see E symbol on notification bar.
- In dial-er simply dial *#*#4636#*#*.
- Testing application gets launched
- Go to Phone information
- By default it will be GSM Auto PRL as preferred network type.
- Change the set preferred network type as WCDMA only, this option is present above TURN OFF RADIO button.
- Now observe the changes, phone network automatically changes to 3G, you can see H symbol on notification bar.
- Do not restart your phone, if you restart, these settings may get changed to default settings.
- Worst case, if you don’t see H symbol, simply tap on TURN OFF RADIO button, this refreshes the network.
This looks like bug, if your phone stop catching 3G and changes its mode to 2G, then follow above steps. This worked well for in my new Moto G phone running on Lollipop OS. Even Kitkat OS phones also may have this issue.