Audi RNS-E Navigation: On the same screen where it asks to enter the code, you can see, at the bottom, the 14-character serial number that begins with AUZ.
Find serial number: The code generator can deduce the unlock code from the serial number of your audio unit.
Chrysler and Jeep Navigations: In some cases, the serial number that begins with T00AM will be visible at the bottom of the screen.
Any model: Whatever the model of the car or radio, there is always a label on the top or side where the serial number can be seen.
Generate code: Simply enter the serial number you just found in the unlock form corresponding to your car's make.