The SRS is virtually maintenancefree and there are no parts you can safely service by yourself. If the SRS air bag warning light does not illuminate when the ignition switch is in the ON position, or continuously remains on, have your vehicle immediately inspected by an authorized HYUNDAI dealer.
Any work on the SRS system, such as removing, installing, repairing, or any work on the steering wheel, the front passenger's panel, front seats and roof rails must be performed by an authorized HYUNDAI dealer. Improper handling of the SRS system may result in serious personal injury.
WARNING
To reduce the risk of serious injury or death, take the following precautions:
Hyundai Elantra AD (2016-2020) Owners Manual: Shift-Lock System. Shift-Lock Release. Parking
Shift-Lock System
For your safety, the dual clutch transmission 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.
...
Hyundai Elantra AD (2016-2020) Service Manual: Compressor oil Repair procedures
Oil Specification
1.
The HFC-134a system requires synthetic (PAG) compressor oil
whereas the R-12 system requires mineral compressor oil. The two oils
must never be mixed.
2.
Compressor (PAG) oil varies according to compressor model. Be sure to use oil specified for the model of compress ...