You need to have your code handy.
4 digit code. Listed in your owners manual or available online if you've bought
a replacement.
Enter the 4 digit code using the radio station preset buttons 1-4. Press each
button repeated until the right number shows (preset 1 for the first number,
preset 2 for the second, etc).
When the numbers are correct, if it doesn't turn on immediately by itself, press
and hold the scan button for 2 seconds.
If that fails, you will see a number "1" in front of the word SAFE on the radio.
Repeat the code input but this time press and hold the SEEK button for 2
seconds.
These early model cassette/cd radios are pretty finicky and none seem to be
programmed the same. Being low or non-existent on the theft list, they
shouldn't even have a security code once they are 12-5 years old.
Look for a decent double din radio and replace it. Less hassles.