DTC C1503-01: TCS/ESC (ESP) Switch Circuit Error: General Description
WARNING: This page is about a different car, the 2021 Kia Seltos. However, it is still accessible from the selected car via links, so may be relevant.
Driver can inhibit the Electronic Stability Control (ESC) control by ESC OFF switch.
When switch signal sends into the Hydraulic Electronic Control Unit (HECU), the ESC warning lamp goes "ON" and the ESC control is stopped and if the next switch signal is inputted again, the ESC control is ready. This function is used for sporty driving or vehicle inspection.