How can I stop CarPlay from automatically connecting when plugged into USB cable?

Hi, I have had this issue as well with my vehicle. The best solution I have found so far, is adding a shortcut to my home screen which brings me directly to the CarPlay toggle for my vehicle.

*My vehicle has wireless CarPlay which may make your situation differ.

The steps to adding the toggle to Home Screen:

1. create a new shortcut in the shortcuts app.
2. under the apps category, select safari -> open urls
3. In the blue URL box, type in this code: prefs:root=General&Path=CARPLAY
4. When finishing up by pressing done, you can add to home screen by holding your new shortcut, and sharing to “Home Screen”

This brings you to your CarPlay vehicle list for which you can manually toggle whether CarPlay appears or not when you enter your vehicle (this I assume works for wired CarPlay as well).

*extra notes: in the upcoming IOS18 update coming this fall, shortcuts may be coming to the control centre, which may make this solution even more efficient.

please reply if someone has found an alternate/better solution.

Look in your car's user guide for the infotainment system section and see if it offers a way to turn off automatic activation. That is an option in the Infotainment system, not on the iPhone.