TECHNICAL SERVICE BULLETIN: SERVICE ACTION: HCU/LDC LOGIC IMPROVEMENT FOR P-DTC (SA484) - This bulletin provides the procedure to update the software logic of the Hybrid Control Unit/Low Voltage DC/DC Converter (HCU/LDC) system on some 2020-2021MY Niro HEV (DE HEV) and Niro PHEV (DE PHEV) vehicles produced in the date ranges shown below, which may incorrectly set a Power Train Diagnostic Trouble Code (P-DTC).