Audi A4 (8K) Comfort System
From Ross-Tech Wiki
Caution!
- Do not save a value of 0 to channel 00 since this can cause keys to be erased, even if you do not have the PIN code for the vehicle. This can cause none of the keys to allow the car to start, likely resulting in the car being flatbedded to an Audi dealer for repairs. It's quite a poor design on Audi's part, if you are able to erase keys without a PIN code yet one is required (or a more involved challenge, etc) to match them.