How do you find the anti-theft system code or how do you disable it?

Hi, I am assuming this is for a 3000GT To answer your question about the alarm. Put the window down , lock the door with the key, immediately,look inside at the dash and you should see a security light to the bottom left of the speedometer that will stay on for app 20 seconds. Open the door from the inside, once the security light goes out. The alarm should start. Unlock the door with the key and the alarm should shut off Hope that helps.

Another possibility, given the vagueness of the question, is that you're asking how to get the code for the radio. Just get the serial number from the top of the factory radio (just pop off the radio bezel, undo the four screws, and pull the radio out a little way) and call your local Mitsubishi service center, they'll tell you the unlock code for the radio