Samsung Galaxy A3 freezes once connected to car's Aux

[Kierengoddard]

My Galaxy A3 freezes as soon as I insert the car's Aux. It stays like that until I press the home button, which makes the phone restart. I've recently traded in my Micra for a Fabia (both 2009) and it worked fine in the Micra and the Aux is the same. But everybody else's phones work fine in the Fabia except mine. Any ideas?