Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
I presume that the AVH device is showing a blank screen with spaces for a code, or something similar.
If so, that's an anti-theft mechanism in the circuits of the AVH device.
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. The entering of an obscure code is required before one may use the radio or stereo etc. again.
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 # ***** the device and according to the maker and model.)
I advise that you take the car to a dealership for that brand of car, and have them generate and enter the code for your stereo.