Step 1. Check your ISP/carrier's coverage area and make sure you are within range. If not, then that could affect your phone's data service or signal strength. You may need to contact your ISP to verify with them the exact network coverage area.
Step 2. Check the SIM card and make sure it is properly installed or inserted. Also make sure you are using the right SIM card on your device. Apple iPhone 5 (16GB) variant uses 4G nano SIM cards. Incompatible SIM types would also cause data connection issues to occur on the device.
Step 3. Verify Airplane Mode settings on your iPhone and ensure it is turned OFF or disabled. To check Airplane mode settings on your iPhone 5 (iOS 6 version), just tap Settings from the home screen. From Airplane mode screen, drag the Switch left or right to enable or disable the feature.
If you are using the iPhone 5 (iOS 7 version), tap Settings from the Home screen and select the Airplane Mode switch to enable/disable the feature. An indication that the Airplane Mode is enabled or turned ON is the green position of the switch.
Step 4. Check Data settings and make sure data is turned ON. To check whether data is enabled or disabled on your iPhone 5, select Settings from the Home screen ->Select General->Cellular, and then drag the Cellular Data switch left to right to turn the feature on or off.
Step 5. Be sure to enable LTE 4G on your device. Select Settings from the Home screen and then select General->Cellular, and drag the Enable LTE switch left or right to turn the LTE 4G data on or off.
Step 6. Be sure to turn on data roaming on your device.
Roaming charges may be incurred for enabling data roaming on your iPhone. You may contact your ISP for further inquiries about roaming services and charges.
Step 7. Perform a Soft Reset or Reboot your iPhone. A soft reset has been known to resolve several issues on iPhone devices, including data connection problems on the iPhone 5. In most cases, a soft reset won't affect data on your iPhone.
Here's how to perform a soft reset on the iPhone 5:
- Press and hold the Power/Sleep button.
- Slide the power switch right. Doing so will power off the phone.
- Allow the phone to power off for some moments.
- Once the phone has finished powering off, press the Power/Sleep button to power it on.
- Unlock the device by sliding the unlock switch right.
Steps to reset network settings on the iPhone 5:
- Press and hold the Power/Sleep button, and the Home/Menu button simultaneously for about 10 seconds.
- When prompted with the slide to unlock screen, just ignore and continue to hold the Power/Sleep button and the Home/Menu button. This will power off the phone.
- Keep holding the Power/Sleep button and the Home/Menu buttons until the Apple logo appears.
- Release the Power/Sleep button and the Home/Menu buttons when the Apple logo displays on screen. This process may take several minutes, so just wait until it is completed.