What are Mitsubishi factory radio codes used for?

The Mitsubishi radio code is an antitheft measure designed to make a radio from a Mitsubishi vehicle inoperable if it is detached from the battery. However, the radio will request a code anytime it loses power, which can also occur if the battery dies or is replaced.

Mitsubishi radio codes are numerical security codes consisting of four digits. When a radio in a Mitsubishi vehicle loses power, either because the battery is dead or the device is no longer attached to the battery, the radio will disable itself. The display will read CODE or OFF until the correct code is entered. If the code is not entered, the radio will not work.