bluetoothheadphonesiosiphone
On my iPhone 6 I see a headphones symbol that only appears when I increase or decrease the volume. I have no headphones plugged in.
Maybe related, I am also unable to get a sound notification, and for all calls I can’t hear the voice. I don't use a Bluetooth headset and I've never changed any settings.
I've had this iPhone for just one week. Is this a hardware or software problem? If software, how do I resolve it?
If your stereo does not register that it supports the A2DP profile, then it likely will also not handle A2DP communication. It is not as simple as finding an app that will "fix the problem", because the problem is likely that your Stereo does not support audio playback. The level of difference between A2DP for audio playback and HSP for maintaining calls is enormous.
Perhaps you may be able to talk to the dealer and see if there is a firmware update for the stereo itself, something they can do to enable this feature. But otherwise, no App can solve it alone.
The best step to isolating your issue would be to collect some data about the bluetooth environment where you are using your mac. Radio waves come and go with other devices, new phones, degrading antennas and changes in bluetooth firmware.
The Bluetooth Explorer is the best tool I have found to troubleshoot bluetooth hardware and data. It's free as part of Xcode from the Mac App Store.
You can debug data issues, see the protocols that connected devices are using, and get to all manner of engineering data relating to bluetooth such as errors, relative signal strength indication (RSSI). It's hard to tell if this will help you, but it lets me know when a microwave or home phone was causing noise issues on several occasions when my hardware was otherwise working properly.
Best Answer
Always a good place to start is to shutdown and reboot your iPhone. If that doesn't work then it's time to investigate further.
If a reboot has no effect, is it possible that your iPhone is connecting to some sort of Bluetooth device? It may not necessarily be a headset (I know you said you don't use one) - it could be a speaker, a receiver, headphones, etc.
The next time this happens, the first thing I would do is go to Bluetooth settings at Settings > Bluetooth and check to see if any devices are listed there? If you see anything you don't recognise or ever want connected, tap on the blue ⓘ symbol on the right of it and select Forget This Device.
Another troubleshooting step you can take is to disable Bluetooth altogether for a while to see what difference, if any, that makes. Once again, you can do this at: Settings > Bluetooth.
If none of this helps, you could check your headphone socket to make sure it's clear of any debris. You can also plug some headphones in and see how your iPhone behaves and then unplug them again.
Finally, you do have various Reset options available to you at Settings > General > Reset. You could start with the Reset Network Settings option (note this will reset Wi-Fi networks and passwords, mobile network settings, VPNs, etc.).
Otherwise you could do a full backup of your iPhone and then do a full reset of all content and settings (also available at Settings > General > Reset). This erases everything, so make sure you've done a full backup so you have something to restore from!