2019 C300 Car Port Phone Calls - No one can hear me
Thread Starter
Newbie
Joined: Jan 2024
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C300
2019 C300 Car Port Phone Calls - No one can hear me
Hello,
I've been having a recent issue with my 2019 C300. When I plug my phone into the USB for car play and make a phone call, the people on the other line cannot hear me. My sound is very low. I've brought this to two different Mercedes dealerships in my area and they both tried playing with settings and updating the software, etc. None of that worked. I've tried to change the phone, plug, etc. I feel like the Mercedes dealerships are just giving me an excuse at this point to not find out what the issue is but this is super annoying on my end. The last dealership I went to didn't even test out the system. They had my car for 3 days and did a software update and didn't check that it worked. Then gave me excuses. I just want to find out what the issue is and fix it. Anyone else have this issue?
I've been having a recent issue with my 2019 C300. When I plug my phone into the USB for car play and make a phone call, the people on the other line cannot hear me. My sound is very low. I've brought this to two different Mercedes dealerships in my area and they both tried playing with settings and updating the software, etc. None of that worked. I've tried to change the phone, plug, etc. I feel like the Mercedes dealerships are just giving me an excuse at this point to not find out what the issue is but this is super annoying on my end. The last dealership I went to didn't even test out the system. They had my car for 3 days and did a software update and didn't check that it worked. Then gave me excuses. I just want to find out what the issue is and fix it. Anyone else have this issue?
Out Of Control!!
Joined: Nov 2018
Posts: 11,430
Likes: 5,336
From: San Francisco Bay Area
2019 C63CS
As said above, you are in the wrong forum, but it is not quite clear from your post if this issue only occurs when making phone calls via CarPlay or also if the phone isn't plugged in and connected through Bluetooth. Also, does your voice command system still work? I had a similar issue with my 2019 C63S after I had some work done on the headliner. I first noticed it because the voice command system didn't hear me anymore. Turned out there was some paper under the headliner that blocked both microphones. Not sure if that paper is supposed to be there or something they left in there when they fixed the rattle, but they ended up removing the microphone covers and cutting out the paper that was blocking them and now everything is working again.
Thread Starter
Newbie
Joined: Jan 2024
Posts: 2
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C300
thanks for letting me know the right forum for this. I can repost there but my Bluetooth, car play and voice command all do not work which leads me to believe it’s the microphones.
As said above, you are in the wrong forum, but it is not quite clear from your post if this issue only occurs when making phone calls via CarPlay or also if the phone isn't plugged in and connected through Bluetooth. Also, does your voice command system still work? I had a similar issue with my 2019 C63S after I had some work done on the headliner. I first noticed it because the voice command system didn't hear me anymore. Turned out there was some paper under the headliner that blocked both microphones. Not sure if that paper is supposed to be there or something they left in there when they fixed the rattle, but they ended up removing the microphone covers and cutting out the paper that was blocking them and now everything is working again.
Out Of Control!!
Joined: Nov 2018
Posts: 11,430
Likes: 5,336
From: San Francisco Bay Area
2019 C63CS
Yes, I bet your microphones are blocked as well if nothing that uses the microphones works or a connection came loose. There are diagnostics procedures to test the microphones. Sounds like the dealerships you've been to kinda suck, but it's fairly straight forward to diagnose if the microphones work or not. Have you told them that voice command etc. doesn't work, either?
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Joined: Sep 2025
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I had the same issue, and it turned out my calls were routing through my voip provider by default, not my actual mobile carrier. Since the car didn’t handle that well, people couldn’t hear me. Once I changed the calling option on my phone to use the carrier instead of the voip provider when connected via Bluetooth, it fixed everything right away.
Last edited by Fashionylem; Oct 14, 2025 at 12:02 PM.
