For your safety, the automatic transmission has a shift-lock system which prevents shifting the transmission from P (Park) into R (Reverse) unless the brake pedal is depressed.
To shift the transmission from P (Park) into R (Reverse):
1. Depress and hold the brake pedal.
2. Start the engine or place the ignition switch in the ON position.
3. Move the shift lever.
Hyundai Sonata LF 2014-2019 Service Manual: Components and Components Location
Components
1. Memory power seat unit (PSM)2. IMS control switch3. Outside Mirror
...
Hyundai Sonata LF 2014-2019 Owners Manual: Charging System Warning Light
If this warning light comes on while the engine is running, the battery is not
being charged. Immediately turn off all electrical accessories. Try not to use electrically
operated controls, such as the power windows. Keep the engine running; starting
the engine will quickly discharge the battery ...