hi. I had same issue. I could not drive anywhere using turn by turn navigation, and GPS was messed up.
- Tried doing a hard reset
- Tried resetting iphone (content and network)
Nothing worked
Solution:
Make sure you have itunes installed first.
- Plug your device into your computer with a USB cable.
- Turn off the device.
- Hold the Power button for 3 seconds.
- Hold the Home and Power buttons for 10 seconds.
- Release the Power button but keep holding the Home button.
- After about 15 seconds you will be alerted by iTunes saying that it has detected a device in Recovery Mode.
Do a full restore but back everything up first.
Worked for me. I can only conclude that a iphone update got corrupted and software prevented GPS from working. A restore without iTunes will use the same version that is on your phone, while iTunes will download a non corrupted copy for you. Please note iTunes download was over 2GB so you will need time.