If the Smart Key is not working properly, try replacing the battery with a new one.
Battery Type: CR2032
To replace the battery:
1. Pry open the rear cover of the smart key.
2. Remove the old battery and insert the new battery.
3. Reinstall the rear cover of the smart key.
If you suspect your smart key might have sustained some damage, or you feel your smart key is not working correctly, contact an authorized HYUNDAI dealer.
Information
An inappropriately disposed battery can be harmful to the environment and human health. Dispose the battery according to your local law(s) and regulation(s).
Hyundai Sonata LF 2014-2019 Service Manual: Front Seat Belt Buckle Components and Components Location
Component Location
1. Front seat belt buckle
...
Hyundai Sonata LF 2014-2019 Service Manual: Side Impact Sensor (SIS) Description and Operation
Description
Side Impact Sensor (SIS) system consists of two P-SIS which
are installed at each center of the front door module (LH and RH) and
two SIS which are installed at each center pillar nearby (LH and RH).
Side Pressure Sensor is also called P-SIS because it detects pressure due to col ...