To unlock the Chevy factory radio, you need to first press and hold presets 2 and 3 for about 10 seconds to get the first 3 digits you need. Next, press the AM FM button and get the second 3 digits. Now, you can call 1-800-537-5140. You will be asked to enter a code, enter 202107 and press * . Enter the 6 digit code from the radio and they will give you another code to unlock the radio. Lastly, press HR button and set the first 2 numbers, then press minute button and set the two last numbers.