Well, no. That stands to reason if the Administrator and Guest passwords have been set, rather than being in the default (no-password) status.
I'm sorry to say there is no procedure for clearing the passwords or a reset of them, aside from what you have already tried.
An activation code for a car radio or car stereo etc., is an anti-theft feature. When the device is removed from the car, the battery power is interrupted to it, and this activates the anti-theft feature.
Sometimes this anti-theft feature is activated when no theft is involved, for instance:
- when a car stereo is sold, after being taken out of a car, by its legitimate owner.
- when a car's battery has been disconnected for servicing of various sorts or in the event of car battery failure.
The code is very hard to 'generate' or hard to find. It would not be an effective anti-theft deterrent otherwise. I have not the means to generate the code for you (though I believe it is generated from the serial # of the device and according to the maker and model.)
I advise that you take the car to a dealership for that brand, and have them generate and enter the code for your stereo.
I have Opted Out also, opening the case to any other Expert here that might have a better answer.