I've had the s6 for almost a year and have had constant problems with bluetooth calls on my 2013 Honda CRV. It's on the calls. If it's just bluetooth audio it's fine. The bluetooth will drop 4-5 times in a 30 minute drive and then reconnect in a few seconds. I brought this up to Verizon a very long time ago and they said to turn off the wifi b/c it might be interfering and I have done this. This has not fixed it. It seems as my call jumps from cell tower to cell tower as a I drive, it's interfering with the bluetooth.
On a side note, I now have the s7 edge and successfully did the 30 minute drive two days in a row with no drops. But on the third day it dropped once and I am very nervous I am going down the same road as the s6. I can't put up with this issue again.
Does anyone have any ideas or insights as to what causes this? Thanks