Support Bluetooth: paired but no connection

The first 2 days after I got my ZTE Racer I had no problem connecting the Racer with my car (Bluetooth). But now suddenly i can't get a connecting anymore. In my settings I see my device is 'paired but not connected'. If I try to connect from The Racer, it doesn't work. If I try to connect from my car, then there's a connection for about 1 or 2 seconds. Then the connection is aborted. Can someone help me with this?

 

Strange, yesterday, after a factory reset, the bluetooth worked well. But today it didn't work no more. Again: connection aborted after 2 seconds.

 

OK, this is what I did. A factory reset (for the 2the time). The bluetoothconnection works and is not aborted. I did not install apps, I only did change the language and added my google-account. After this the bluetoothconnection was aborted and could not be restored (or only for 2 seconds). Something with the dataconnection? I really need the bleutoothconnection in my car. Someone an idea?