If the remote key does not operate normally, you can lock or unlock the door by using the mechanical key.
Press the release button then the key will unfold automatically.
To fold the key, fold the key manually while pressing the release button.
Hyundai Sonata LF 2014-2019 Service Manual: Hood Latch Release Handle Repair procedures
Replacement
1.
Using a socket (B), remove the hood release handle (A).
2.
Install in the reverse order of removal.
•
Make sure the hood latch cable is connected properly.
•
Make sure the hood locks / unlocks and opens / closes properly.
...
Hyundai Sonata LF 2014-2019 Owners Manual: Engine Start/Stop Button
Whenever the front door is opened, the Engine Start/Stop button will illuminate
and will go off 30 seconds after the door is closed.
WARNING
To reduce risk of serious injury or death, NEVER allow children or any person
who is unfamiliar with the vehicle to touch the Engine Start/Stop button or re ...