Hi there AL26,
Thanks for reaching out to Apple Support Communities. It sounds like you’ve run into an issue with CarPlay and your iPhone. We’ll be happy to help.
Let’s check a few things. If you’re using your iPhone with CarPlay for the first time, check to make sure it’s available in your country: Apple CarPlay Available on iOS.
Check to see if the vehicles you tested with are listed on this page: More than 600 models to choose from.
Try these steps: If you need help with CarPlay
Make sure to remove your case if applicable, you’ll want to test without it. Ensure CarPlay is not restricted in: Settings > General > CarPlay, as well as Settings > Screen Time > Content & Privacy Restrictions > Allowed Apps.
Forget the car stereo from Settings > General > CarPlay > [stereo name], and forget the iPhone from the settings (stereo user guide for instructions). Then rename the iPhone in Settings > General > About > Name.
Reset network settings on the iPhone. If you’re using wired CarPlay, test with a shorter Apple approved Lightning cable. If you don’t have a shorter cable available, test with another Apple approved Lightning cable. Power on your vehicle and allow the stereo to fully wake before connecting the iPhone and test again. If the issue continues, you can use the following link to get connected for further assistance: Contact Apple Support.
Best regards.