Hey how are you
what have you done so far
there a shift interlock solenoid under shifter you need to check ? when press brake pedal do you hear it clicking ti release the shifter
do you have a capable scanner to read Hyundai fault codes ?
did you check battery for 12 volts ?
are the brake lights working ?
Did you try a master reset
Master reset Procedure
1- Disconnect Battery Cables ( Negative & Positive Cables )you can use any electrical wire as an extension if battery cables don't reach .
2- Hold cables Together for 60 secs ,then let go
3- Wait 30 minutes
4- Make sure all doors are closed
5- Reconnect battery Cables
6- Lock & unlock the vehicles using the key from driver door side (if you have a key fob with no blade key, just lock & unlock using the key fob buttons)
7- Enter the vehicle and attempt to start
Please let me know & we go from there
ASE Certified Technician