To clear the average fuel economy manually, press the OK button (reset) on the steering wheel for more than 1 second when the average fuel economy is displayed.
Kia Niro (DE HEV) Owners Manual: Engine compartment fuse panel (Battery terminal cover)
Engine room compartment fuse panel
Circuit (PCB Block)
Relay
...
Kia Niro 2017 (DE HEV) Service Manual: Motor Control Unit (MCU) Components and components location
Components Location
1. HPCU assembly
...