iPhone 4 seemingly muting itself (but not activating the mute function) for no reason

[Possessed_iPhone]

I am hoping that some brilliant soul on here can help with a rather infuriating issue I am having with my iPhone 4. For some reason I can hear people fine but people on the other end of the call can't hear me... Not through regular talking mode, not through speaker mode or even when my phone is synced with my truck's entertainment system using its dashboard microphone. There is no sound at all, like its muted. The mute function is not actually engaged, mind you, it just acts that way. However, if I take the Sim card out and put it back in, then the phone works perfectly for a while and then for no apparent reason acts muted again. Sometimes it will work for one call, sometimes for a day or more but it always returns to its mute-like state. I have tried three different Sim cards from two different carriers, and all did the same thing. I have been to the Apple store numerous times, and they are at a loss. The phone is obviously now out of warranty, so all they could suggest after doing multiple hard and soft resets was that I needed a new phone. I am still able to text, use the internet... everything except talk. The only other thing it does is that it sometimes will activate voice control for no reason when I am listening to music, but that's relatively rare and I do not know if the two are related. I should also note that this is a factory reconditioned iPhone. I have looked all over the internet and not found anything describing this problem. I am comfortable taking it apart, so any advice anyone has would be greatly appreciated. Thanks!!

- I should also add that voice memo works fine, so between that and the fact that the voice function temporarily works perfectly following a Sim card swap I don't see how it could be either of the microphones.

 

[BatMoto]

I have a similar problem. In my case, restoring the phone seems to fix the problem. Actually I restored it once and it worked ok. I then reinstalled my apps and it still seemed to work ok but after a while the problem came back. I restored again and am in the process of reinstalling my apps one by one and checking calls every time, in hopes of finding an offending app. Let me know if you find a cure.
Thanks.

 

[Geoffers]

I have a similar problem. In my case, restoring the phone seems to fix the problem. Actually I restored it once and it worked ok. I then reinstalled my apps and it still seemed to work ok but after a while the problem came back. I restored again and am in the process of reinstalling my apps one by one and checking calls every time, in hopes of finding an offending app. Let me know if you find a cure.
Thanks.

I encounter a similar problem, and I think it has something to do with either engaging Bluetooth and/or plugging into my car's audio system. So, the way to unmute is as follows go to settings/general/accessibility scroll down to "assistive touch" and set to "on". This will result in a greyed out icon appearing on the screen. When you touch this icon, it will bring up a 4 icon panel, touch the "device" icon, which will bring up a second panel, the right hand "bell" icon will show mute/unmute depending on the state of the ringer. Use this icon to toggle the ringer staus to unmute and exit the accessibility app. The ringer volume should be restored and doesn't require a phone reset. I leave the accessibility feature activated all the time, it doesn't really impar the use of the iPhone.

 

[deolgoatlady]

I encounter a similar problem, and I think it has something to do with either engaging Bluetooth and/or plugging into my car's audio system. So, the way to unmute is as follows go to settings/general/accessibility scroll down to "assistive touch" and set to "on". This will result in a greyed out icon appearing on the screen. When you touch this icon, it will bring up a 4 icon panel, touch the "device" icon, which will bring up a second panel, the right hand "bell" icon will show mute/unmute depending on the state of the ringer. Use this icon to toggle the ringer staus to unmute and exit the accessibility app. The ringer volume should be restored and doesn't require a phone reset. I leave the accessibility feature activated all the time, it doesn't really impar the use of the iPhone.

I've been doing this also but find it irritating. Wish someone knows a permanent fix.