Software

Use a plastic pry tool to remove the outer dash trim surrounding the radio. Unscrew the four Torx T20 screws securing the unit. Slide the radio forward to inspect the casing.

The calculator uses a proprietary decryption algorithm (often based on a lookup table and a polynomial checksum) to convert a 14-character serial number into a 4-digit unlock code.

Elias froze. He looked at the harmless gray box on his screen. Then he looked at the radio humming on his desk.

: Local VW dealers can retrieve codes using the serial number and VIN if the radio is original to the vehicle.