Operating Door Locks from Outside the Vehicle
Mechanical key

If you lock the driver's door with a mechanical key, all vehicle doors will lock. If you unlock the driver's door with a mechanical key, the driver's door will unlock and the passenger doors will unlock according to the current two press unlock setting.
Once the doors are unlocked, they may be opened by pulling the door handle.
When closing the door, push the door by hand. Make sure that doors are closed securely.
Remote key

To lock the doors, press the Door Lock button (1) on the remote key. Press the Door Unlock button (2) on the remote key, the driver's door will unlock. If you press the Door Unlock button on the remote key again within four seconds, then all the doors will unlock.
Once the doors are unlocked, they may be opened by pulling the door handle.
When closing the door, push the door by hand. Make sure that doors are closed securely.
Information
Immobilizer System
Smart keyHyundai Elantra AD (2016-2020) Service Manual: Receiver-Drier Repair procedures
Replacement
1.
Remove the condenser.
2.
Remove the cap (A) on the bottom of the condenser with a L wrench.
Tightening torque :
9.81 ~ 14.71 N.m (1.0 ~ 1.5 kgf.m, 7.2 ~ 10.8 lb-ft)
3.
Remove the receiver-drier (A) from condenser using a long
nose plier. Check for crumbled recei ...
Hyundai Elantra AD (2016-2020) Service Manual: Adaptive Front Lighting System Description and Operation
Description
AFLS Unit (ECU)
AFLS located in Cockpit Module is provided information of vehicle. (steering wheel signal,vehicle speed, inclination of vehicle)
Based on provided information, it calculates algorithm and adjust Low beam of H/Lamp.
It transmits driving information by using LIN prot ...