Audi A3 2004 to 2013 all keys lost requires 7th byte CS code via eeprom. Here is the trick. The job can be done by Autel IM508/IM608 with APB112 emulator directly via OBD without removing immo box. It is easy to do as long as no one else touched it and does under lost keys. It is safe because there is no working transponder. Need good power as well.
Model example: Audi A3 2005.
Make device and vehicle connection
Select Immobilizer-Audi -A3- 2004 to 2013 -Control Unit- Conti CAN Ins (CDC32XX+ 24C32 A3TTR8) immobilizer- Read Immo Data of ECM
Detecting engine type
it takes sevral minutes to read immo data
Read CS, PIN and ECU software number and confirm
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.
This model has smart key. Here we use automatic mode.
Enter the first 6 bytes of the CS code of the vehicle
Connect the APB112 smart key simulator and then press OK
Select Automatic search
Follow steps below to search for 7th byte
Search 7th byte CS code successfully.
You can now add key and learn key.