Remove cas4 read and save dflash and pflash to your computer.
You will also need the htag key programmer .
You also may need the ISN.
Start Autohex , goto Coding/Programming ,
It will connect to available modules.
Select Key Learning
You will see the key frequency and immo system.
To enable or disable a key select 1.
Here you can also see whuch keys are enabled, used etc.
To program a new key select 2.
Now load the previously saved cas4 eeprom data. (Dflash).
Now select the key number you wish to program.
It will ask if you are sure , press yes.
Connect your htag programmer .
Press the tick.