Lost every A4 key?
With no A4 key left, a 2002 to 2016 car is usually still finished where it sits. Flip-key cars keep the immobilizer data in the instrument cluster, which may be pulled for a bench reading; slot-key cars keep it in the comfort module.
The job adds $60, making it $259 for a flip-key A4 or $409 for a slot-key A4, and the car forgets any key that went missing. Proof of ownership is required: a registration or title plus matching photo ID.
Phone first if a 2017 or newer A4 has no working key left. Certain cars on this platform need a replacement key or module that Audi supplies for the VIN, and if yours points that way, the call ends with that answer and a list of what to take to the dealer, not with a van in your driveway.