Hyundai Ioniq Hybrid 2020 Owner's Manual page 326

Driving your vehicle
Engine Start/Stop Button Positions
Button Position
OFF
To turn off the vehicle, press the Engine
Start/Stop button with shift lever in P (Park).
When you press the Engine Start/Stop but-
ton without the shift lever in P (Park), the
Engine Start/Stop button does not turn to the
OFF position, but turns to the ACC position.
ACC
Press the Engine Start/Stop button when the
button is in the OFF position without depress-
ing the brake pedal.
Some of the electrical accessories are
usable.
5-10
Action Notice
If you leave the Engine Start/Stop button in the
ACC position for more than one hour, the bat-
tery power will turn off automatically to prevent
the battery from discharging.