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Glitchy phone call audio on bluetooth car kit


I have a nokia 6 on Oreo 8.0.0 (00WW_5_22A), when connected to the the handsfree kit in my car every few minutes the phone call audio goes all glitchy (sounds like the person at the other end is underwater) for a few seconds making it impossible to have a decent conversation.

I have tried all manor of tests at Nokia's support chat request and nothing is making the problem better. The things I have tried so far are;

-Resetting the network settings

-Setting the TTY mode to full

-Doing a soft reset

-Doing a hard reset

Does anyone have any ideas how I can make my phone usable with a bluetooth handsfree kit?

Many thanks


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I have this problem since first os version, 7.0. With 7.1.2 and december update, solved at 80%. Now, with Oreo update, again the problem.

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Having fast regular updates is supposed to be a positive but it seems that some of them are really only beta quality.

Tech Wizard

Hi Jason,

Maintaining good voice quality in a moving car is a challenge for the cell network and the phone. Depending on the mobile operator, you may get better results if the preferred network type is set to 3G or 2G instead of 4G.

- Did you try this already?

Regarding Bluetooth interoperability issues, it is unfair to blame only the phone, or only the handsfree.

- How does another phone with the same SIM perform with the handsfree kit?

For reference please, and for others to maybe provide better answers, which mobile operator/carrier in what country, and what is the make and model of the handsfree kit?


Hi Hans, Thanks for your reply. So I originally had been wondering if it was another cause so had already tried: - Sitting in a layby with a good signal whilst on a call - whilst on a call changing to loud speaker mode on the phone (which did resolve the problem) - using my old Samsung s7 with the same sim connected to the car kit (which didn't have the problem) Do to another issue I have with the phone (it takes ages to connect out going calls as my provider doesn't support volte) my phone is set to 2g / 3g mode anyway. On Friday I spent almost 2 hours on the Nokia support chat and after all sorts of tests their advice was to wait for this months security update but couldn't confirm that it was a known issue that was due to be fixed. Seemed to me they didn't know what else to do and were trying to get rid of me! Kind regards Jason
Sorry I forgot to mention that I am in the UK on plusnet mobile. Kind regards Jason

Tech Wizard

Thanks for the follow-up Jason. It seems you already tried everything except replace the phone or the handsfree kit.

Plusnet Mobile = EE (Huawei network). Both EE and HMD/Nokia must be aware of the 4G and VoLTE issues with Nokia 6 at EE. There are several posts regarding this in the forum. - Hopefully the Bluetooth call audio quality improves when the basic connectivity issues is sorted out.

Please let the forum know how it goes.

Best regards,


I have test all recomendations and nothing. I am in Spain, with Movistar net and I have try in 2012 Mercedes Eclass original bluetooth, 2013 Mercedes Viano original bluetooth and in 2017 Mercedes Eclass original bluetooth. My previous phone, Microsoft Lumia 640 with the same SIM and without problems. In the previous version, puting the volume in low mode, partially solved. Now, this solution is not working. Regards

Thank you for posting, it's nice to know it's not just my handset! I've had to go back to using my Samsung as I do a lot of driving for work and it's important for me to be able to take calls whilst driving.

I really like the handset, I even prefer it to my S8 but the software updates just aren't good enough.

Kind regards


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It is not only your mobile. I had bougth 3 units of Nokia 6 and I have this problem with 3 units in all my cars. The answer of the help chat was that the problem is in all my Mercedes-Benz bluetooth systems and that the phones works perfectly. They recomend me to repair the original bluetooth or change for aftermarket one,  Of course, I will change the "nokia" phones before touch anything in my cars. Regards

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Tech Wizard

FYI, Mercedes-Benz provide a comprehensive mobile support website at

There's an update for SIM Access Protocol and audio quality.

MB has tested and approved Nokia 8 for their 2017 models (with limitations regarding music playback control).

Radio interference may affect Bluetooth audio quality:
Toggle WiFi off during Bluetooth pairing and while troubleshooting.

In Settings > Securiy & location > Location > Scanning = Try toggle off both Wi-Fi and Bluetooth scanning to see if this makes a difference - but keep location On during pairing and use.

In Settings > Connected devices > Bluetooth = Try temporarily delete other devices (that the phone may be searching for) and close other apps that use Bluetooth.

Of course it should 'just work'. I just wanted to repeat, regarding Bluetooth interoperability issues, it is unfair to blame only the phone, or only the handsfree kit.

Car infotainment systems is much more complex than my legacy BH-111 Bluetooth headset and its 4-way remote control box, so I'm out.


Hi. This week I have done your recomendations, and I have the problem still.

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Tech Wizard

Thanks for trying and for feedback.

If the Update_SAP_V4 download from the MB website for the car radio, and the general Bluetooth troubleshooting steps does not improve the call audio stability, then the next step is a Mercedes workshop.


I have the same issue in my wife's LandRover Discovery  Bluetooth systems, 

continuously broken audio, it is impossible to understand the communication. Maybe there is something I have to disable to improve the audio quality. 

Please Help,


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Sorry, but I am not agree with the solution of visit my Mercedes dealer, because the problem is only with Nokia phones. The best choice and cheap solution, change the mobiles. We are a professional drivers company and we can't work with this mobiles. A sugestion: if you need to use the mobile driving, choice another mobile brand. We are waiting around a year for a solution and still nothing. We don't need the rest of features of the mobile, only calls and emails, so I don't know in the mobile has more issues. Regards

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