DTC Description
WARNING: This page is about a different car, the 2021 Hyundai Kona. However, it is still accessible from the selected car via links, so may be relevant.
Checking output signals from both Stop Lamp Switch when all of them are On or OFF simultaneously, if abnormal signal is detected for 60 seconds or longer, an error is recognized. PCM sets DTC P0504-00 if the PCM detects signal of the brake warning lamp and brake switch do not correlate within the pre-determined time.