Hyundai Veloster User Manual page 74

AUX mode
Symptom
No sound is heard in the AUX
mode.
A distorted noise is heard in
the AUX mode.
7-6
Possible cause
Poor connection
Device powered by your
vehicle's battery power
Solution
Disconnect the cable from the AUX port and reconnect it correctly.
Connecting the device with the power cable plugged into the
power jack may cause a distorted noise. Unplug the device's
power cable from the vehicle.