Bluetooth fault

[Likiu]

Le he hecho un diagnóstico al Bluetooth y dice que funciona correctamente, pero no consigo enlazar con algunos auriculares y con Bluetooth de algunos coches.

He comprado un coche nuevo, enlaza el telefono,escucho música, se cargan los contactos pero no puedo enviar y recibir llamadas.

No puedo marcar la casilla de "audio en llamadas" en ajustes del Bluetooth.

¿Que puedo hacer para solucionarlo?

Gracias.

I have made a diagnosis to the Bluetooth and says that it works correctly, but I can not connect with some Bluetooth headsets and some cars.
I bought a new car, linked the phone, listen to music, the contacts are loaded but I can not send and receive calls.
I can not check the "audio in calls" box in Bluetooth settings.
What can I do to solve it?
Thank you.

GT

[YoGem]

@Likiu I think there is something not working properly and/or that the two devices are not recognizing each other as capable to transfer the audio from phone to the car.

To make it sweet and short, what's the car stereo brand and model? I can connect my C5 to a plethora of car stereos without any problem. So there should be for sure some settings on the car stereo end to enable that function.