The first situation is: the call volume of the mobile phone is not turned on,

The second situation is: the volume of the car navigation system is not turned on, just turn it on;

The third possibility is: the car Bluetooth and the mobile phone are not paired and connected at all

When the mobile phone is connected to Bluetooth, turn on the mobile phone Bluetooth in the mobile phone settings, and use the MEDIA selection key to enter the audio source selection Interface, special instructions,

Select BT. If you want to achieve simultaneous playback of music and navigation without affecting each other, set up the paired device VWRADIO, select MEDIA's BT, and after the mobile phone and the car Bluetooth device are successfully paired< /p>

Open the Bluetooth settings of your phone, click on the small triangle behind the name of the car Bluetooth device, enter the device management, and check whether multimedia audio is turned on.

Music can only be played on the mobile phone music player, that is, mobile phone songs can be played using the speakers in the car, and it does not affect each other with the navigation.

The Bluetooth settings on the mobile phone are divided into 2 independent parts:

1? The phone is connected to the car’s stereo through Bluetooth?

2? Multimedia (including navigation) Send the sound to the car's speakers through Bluetooth? (The default setting of the mobile phone is that once Bluetooth is turned on, both of these will be played from the car's speakers through Bluetooth. But on the car's speakers, you have not selected the sound source as Bluetooth. Most people I chose a USB disk or CD. So there is no sound in the navigation)

If there is no sound in the navigation, there are two methods, just choose one:

1? Set it on the mobile phone. Multimedia sound, play it from your mobile phone or?

2? On the car audio, select the sound source as Bluetooth?

Reference: Baidu Encyclopedia - Car Bluetooth