1. Please confirm whether the mobile phone is connected to the car Bluetooth, and ignore the car Bluetooth if it is connected.
2. Bluetooth has been ignored the Bluetooth of the car or is not connected to the Bluetooth of the car, but there is no sound, please go to APK Settings--Environmental Detection--Detect Microphone Permissions. If there is a program that occupies the microphone, please uninstall the program that occupies the microphone. Turn off or disable the occupation of the contact microphone. If the microphone cannot be released, you can only use the car Bluetooth channel (car Bluetooth channel settings: APK settings-advanced settings-audio channel-choose car Bluetooth, and then the phone connects to the Bluetooth on the car).
3. If the microphone detection is not occupied, then either the car microphone is broken (cannot be solved), or the car microphone cannot be called by the APK (you can only use the car Bluetooth channel, the method is the same as above).
4. If it is a CCPA-MIC model, the product with its own microphone, the Bluetooth channel setting of the car: APK Settings--Advanced Settings--Audio Channel--Select Box.