It could be that you need to install an adaptor. You have the buttons on the radio, but it does not mean that you have it. Will cost you around $ 250.00 excl. the install.
I installed it on my Avenger, very easy to do, just plug and play, it can not go wrong. Try to search on the web (www.mopar.com - got to Dodge, select Journey then accesoirries and finally radio/cd/uconnect)
I hope that you like the Journey and wish that you have a lot of safe milage.