Can't sync iPod to car

One of the reasons I got an iPod( iPod touch 5) is because I can connect it to my car's stereo via the usb port. It works fine with my iPad. As soon as I connect to the usb, My car reads the iPad and plays whatever I had on last. When I plug in the iPod, I get no playlists. I can't start the music player because on the iPod it says accessory connected.
Don't know if anybody has car accessibility and can help me with this question. I kind of think it has to do with the downloading of my music from iTunes because I noticed that on the iPod, the music did not break down into my playlists and creating playlists directly on the iPod is difficult without the split screen to drag music. My playlists did transfer to my iPad no problem.
Any suggestions?

Well, I did something and fixed my issue. I made playlists on my iPod( I was stumped because my playlists on my Mac, transferred to the iPad but only the music and albums transferred to the iPod) once I made up some playlists on the iPod and plugged it into my car, it started to play- go figure. BTW, I erred to mention my car is a 2013 Nissan Altima- many newer cars are putting in a usb port vs the aux plug so others may come across this dilemma in the future. Now I can carry my entire CD collection in my hand . Now, Nissan just needs to make a touch screen rather than the knob controls like the other Japanese car companies