DTC C1817-08: CAN Signal Error Gateway: General Description
WARNING: This page is about a different car, the 2016 Hyundai Sonata and 2015 Hyundai Sonata. However, it is still accessible from the selected car via links, so may be relevant.
Through the CAN line, the EPB ECM receives data from BCM such as Seatbelt, Door, Trunk, Hood and etc. and then operates the EPB system.