It used to work perfectly on my S4. About 4 months ago voice guidance became intermittent or mostly not working. Sometimes a navigation session starts fine with voice guidance for the first few minutes or few turns then it stops. The screen guidance keeps on working, only the voice stop. Which, of course, makes navigation next to useless because it requires the driver to keep staring at the phone display for instructions. An other S4 owner at work has exactly the same issue. I have all the latest updates, Map and S4, and I tried to delete and re-install Google Maps. All the same. Since this is an important feature for me I would really appreciate some advice.