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Once a unit is paired with a specific vehicle, the car's instrument cluster remembers the stereo via CAN-bus communication. If you disconnect the battery, the unit usually automatically unlocks itself when you turn the key, because it recognizes the vehicle's VIN.

A technician opens the RNS-E casing, connects an EEPROM reader programmer to the chip (often a 24C64 or similar memory chip), and dumps the binary file (BIN).

Locate the printed paper label or the engraving stamped directly into the metal side casing.

Sitting on a milk crate in the back of a rusted 2007 Audi A4, Elias pulled a small, silver unit from the dashboard: an . To most, it was a paperweight. To Elias, it was a treasure chest.

You must pull the radio out of the dashboard slightly to read the label.

Insert the four keys into the thin vertical slots on the face of the RNS-E. Ensure the straight edges of the keys face outward. Push the keys in until you hear a distinct click.

Repeat this process until all 4 digits of your PIN are displayed correctly on the screen.