Radio

Have you tired leaving the radio turned on for an hour or two? This will generally reset the radio so you can re-enter the code.

put the car in acc mode, don't start the car, and wait a couple of hours.

if you wait with the car on you need to have a battery charger handy so you dont run the battery down, or you can go for a long drive at least an hour and a half to 2 hours that will reset it

Leave it on 4 one hour straight