To program the spare key fob from your old Q5 to work with your new Q5, you'll likely need to follow a procedure that involves reprogramming the remote to synchronize it with your new vehicle. Before attempting to program the key fob, ensure you have all the necessary information, including the model year and specific instructions for your vehicle. You may find this information in the owner's manual or by contacting a dealership. Depending on the vehicle model and year, there may be a specific procedure to access the programming mode for the key fob. This often involves inserting and removing the key from the ignition a certain number of times or pressing a combination of buttons on the remote and the vehicle. Once in programming mode, follow the instructions provided by the manufacturer or the dealership. This typically involves pressing buttons on the existing key fob and the new key fob in a specific sequence within a certain timeframe. After completing the programming sequence, test the newly programmed key fob to ensure it functions correctly. Test functions such as locking, unlocking, and activating the panic alarm to verify that the remote is working as intended. Once you've verified that the key fob is working properly, exit programming mode according to the instructions provided. This may involve turning the ignition off or removing the key from the ignition.