Most car radio or stereo comes with a code from the manufacturer of the car in order to deter theft, and when the car stereo is detached or removed from the vehicle, or sometimes when the battery of the vehicle is disconnected, the radio cannot be used unless the unlock or security code for it is entered.
In most cases to obtain this code, you will need to access the serial and model number of the stereo and the VIN of the vehicle and then you can again be on your way to use the radio.
There are more ways than one, in which you can obtain the code for your radio in case you are faced in a circumstance and by which it is accessed or obtained also depends on complexity and cost.
For most, some of the options that are basically available but to no obligation to be provided with it being a courtesy service, includes the option to check the user’s manual, check the OEM’s website, call your local dealer, search through free online databases, and you will need to have on hand info. like the make, model, year, and VIN of your vehicle, serial number and model of the radio too.
If for some reason you have a hard time accessing the code from the options mentioned above, then you can always go for a paid service from a local shop or online service to locate or calculate the code, and these services online usually have radio codes of almost all car manufacturers and they are able to generate and provide you the code with the basic serial number of your radio.
You have to absolutely know the procedure in putting in the codes on your radio, especially if this is the first time that you have encountered and done it as several wrong inputs of the codes can lock you out which will allow you to reset the radio before you will have the option to enter the code again.
Just accessing the code may be a daunting task, therefore if you happen to have that code, keep it safe or noted safely where you can have direct access to it personally, so that you will not have to undergo the same trouble again should it recur, and you will not be paying again for the code in case it was bought online, however there are some online services that offer free radio code recovery for your code that was previously ordered from them, so you need not pay again for the same code.