Hi Oliviayml,
Thanks for the post. As I understand it, your CarPlay interface shows as scrambled when you connect your iPhone.
To clarify, it sounds like you might be connecting directly using a cable. Is that right? If so, a good starting point would be to try a different cable.
To troubleshoot further, I recommend working through all of the steps in this resource: If your iPhone, iPad, or iPod doesn't connect to or work in your car. Be sure to verify that your vehicle firmware is updated.
Feel free to reply back if needed. Take care.