Looks like the dealer sends your information to Sirius, that is how they link up your name with the ESN given to the vehicle you bought. Sirius uses the satellite transmission to address your reciever and enable the channels you can listen to while you have an account. Knowing your code only identifies the reciever; there is nothing else you can do with it except give it to Sirius so they can associate the receiver with you the customer, for example when you sell the car to someone else.