Input of Radio Codes

'91 318i E36 Model M40 motor, my son disconnected the battery and then tried to enter the code for the anti-theft radio. The radio is locked up and have tried to let the car sit with ACC on and re-enter to no avail. I have the radio code for this radio, is there any special way to re-enter the code or do I need to actually let the car run instead of just putting it in ACC.

Thanks in advance

In my 87 325 you have to leave the car running not just in acc mode, with the radio on for 1 hour before you can enter the code after 3 attempts with the wrong code. Hopefully their the same.

In my 87 325 you have to leave the car running not just in acc mode, with the radio on for 1 hour before you can enter the code after 3 attempts with the wrong code. Hopefully their the same.

This happened to my 95 325i and the dealer told me to turn the key to ACC for a hour and a half while hooking a battery charger to the battery because it will most likely drain it after the wait enter the code and you should be good to go.