Audi A3 2004 to 2013 all key lost requires 7th byte CS code via eeprom. Here’s the trick.
The work can be done by Autel IM508/Autel MaxiIM IM608 with APB112 emulator directly via OBD without removing the immo box. It’s easy to do as long as nobody touched it and do it under lost keys. It’s safe because there’s no working transponder. Also need good power.
Sample example: Audi A3 2005.
How to do？
Make device and vehicle connection
IM508/IM608 read only 6-bytes CS code
you need to find 7th byte CS
Select Search for 7th byte (all keys lost)
This function is used to search for the 7th byte when all keys are lost. There are 2 search modes: Automatic and manual.
Smart key: Place the apb112 smart key simulator close to the Start/Stop button until the search succeeds.
Blade key: Place the APB112 smart key simulator close to the ignition, insert the non-chip key into the ignition and turn ignition to ON until the search succeeds.
Smart key: Place the apb112 smart key simulator close to the Start/Stop button, and repeatedly turn on and off the ignition until the search succeeds
Blade key: Place the APB112 smart key simulator close to the ignition, and use the non-chipped key to repeated turn on the ignition to ON and then turn it off until search succeeds.
Automatic search is faster and manual search is slower as it requires manually turn on/off ignition until the search succeeds.
Follow steps below to search for 7th byte
Search 7th byte CS code successfully.
You can now add key and learn key.