Possible factors are as follows.

1. If the volume on the car navigation system or mobile phone is not turned on, just turn it on.

2. The music playback programming of some mobile phones (such as Iphone) does not match the docking code of some car models, so you can only answer calls but not listen to music. You need to change the Bluetooth playback frequency band.

3. Multimedia music that does not have car Bluetooth enabled needs to be turned on.

4. The media audio on the mobile phone is not turned off, causing signal interference in the Bluetooth function.

You can connect to the car through Bluetooth on your phone to play music on your phone. The specific steps are as follows:

1. Open the car's multimedia settings and select the Bluetooth function.

2. Turn on the car’s Bluetooth connection function. If the mobile phone is connected, just play it directly through the mobile phone. If it is not connected, click device registration.

3. In the Bluetooth device reminder on the car screen, click Yes to confirm. NOTE: The phone’s Bluetooth must be turned on and set to be visible.

4. In the pop-up interface, follow the prompt information to perform Bluetooth connection operations on the mobile phone.

5. After completing the registration of the mobile phone’s Bluetooth, select the device’s connection switch.

6. Select audio playback through the device.

7. Click to select your mobile phone name to complete the setting of the car audio playback source.

8. Wait for the Bluetooth connection to be completed.

9. After the connection is completed, you can play music.