Here is the instruction on adding a spare key to Audi Q3 VDO 2009+ by xhorse vvdi key tool plus.
Read immo data
Generate Dealer Key
Step 1: Read Immo Data
Connect Key Tool Plus with OBD.
Turn ignition on, press
Immo programming >> Europe >> VW >> Automatically diagnose models >> Start programming
Detect instrument type VDO NEC 2009+ UDS
Select Read Immo data
Get the working key close to antenna
Switch on with working key before press OK. If car has keyless GO, put the working key nearby car coil and switch on.
Select “Login method 1”.
Save immo data
Reset instrument to activate dash after operation finished
Put original key into xhorse key tool plus coil
Select Generate dealer key-load immo data
Upload immo data read above
Select Prepare normal dealer key
Place an unlocked ID48 chip/key into the coil
Make dealer key success
Select Key Learn function
You should backup EEPROM and immo data before learn key
Select programming method: Program keys, get the login code from immo data to log in.
Put original key into igniton switch
Input number of keys to be learnt: 2
Upload immo data saved before
Place 1st key into the car sensing coil and don’t remove.
Learn 1st key
Place the 2nd key close to the antenna and wait
Learn 2nd key success