WARNING: This page is about a different car, the 2014 Hyundai Santa Fe Sport and 2013 Hyundai Santa Fe Sport. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Display - C_CAN Low & High Signal Waveform
Courtesy of HYUNDAI MOTOR AMERICA
Fig 2: Display - C_CAN Bus Voltage Level (High Speed CAN)