Shift-lock system
For your safety, the Intelligent Variable Transmission (IVT) 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.
Shift-lock release

If the shift lever cannot be moved from the P (Park) position into R (Reverse) position with the brake pedal depressed, continue depressing the brake, and then do the following:
1. Place the ignition switch in the LOCK/OFF position.
2. Apply the parking brake.
3. Carefully remove the cap (1) covering the shift-lock release access hole.
4. Insert a tool (e.g. flathead screwdriver) into the access hole and press down on the tool.
5. Move the shift lever.
6. Remove the tool from the shiftlock override access hole then install the cap.
If you need to use the shift-lock release, have your vehicle inspected by an authorized HYUNDAI dealer immediately.
Transmission ranges
ParkingHyundai Elantra AD (2016-2020) Service Manual: Seat Heater Switch Repair procedures
Removal
[Front Seat]
1.
Disconnect the negative (-) battery terminal.
2.
Remove the floor console assembly.
(Refer to Body - "Floor Console Assembly")
[Rear Seat]
1.
Disconnect the negative (-) battery terminal.
2.
Remove the rear door window switch.
(Refer to Power Windows - "Po ...
Hyundai Elantra AD (2016-2020) Service Manual: General Information
General
1.
This measurements are provided as reference for A/S, so it can not be used as specification.
2.
Basically, all measurements in this manual are taken with a tracking gauge.
3.
When a measuring tape is used, check to be sure there is no elongation, twisting or bending.
4.
...