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: Rear Door Window Glass Repair procedures
Replacement
1.
Remove the rear door trim.
(Refer to Rear Door - "Rear Door Trim")
2.
Remove the rear door belt inside weatherstrip (A).
3.
Pull down rear door window glass by pressing the power window glass switch.
4.
Loosen the mounting screws and remove the rear door belt outside ...
Hyundai Elantra AD (2016-2020) Service Manual: Inhibitor Switch Troubleshooting
Fault Diagnosis
Fault Diagnosis for Symptom
Major Symptom Expected Cause Items to Check and Measures Shift lever inoperableFaulty shift cable tensionAdjust shift cable tension(refer to "Automatic Transaxle System – Inhibitor Switch")Faulty shift cable assembly/connec ...