The S-PIN is a 4-digit code that you create for your CUPRA ID during registration that you will need everytime you login in your car, as a security measure, unless you click on "save PIN". For safety reasons, you will need to introduce it in some services, such as Remote ventilation, Remote Auxiliary Heater...
Additionally, you can change the S-PIN from the App if you have already some vehicle enrolled. For that, log in in the App -->go to "Account" in the bottom left of the screen--> your data-->security.