Solved: Honda CarPlay screen goes black upon launch with iPhone 15 Pro Max
Thanks everyone in the forum for providing advice on solving the Honda CarPlay screen goes black problem. I tried all the proposed solutions and none of them worked but working with Apple support, we found and resolved the source of the problem. This may help you as well. If you have a VPN enabled on your phone, disable it and try reconnecting your phone. Apple support said the VPN was blocking access to the server (probably was the server denying access to a VPN address.)
I hope that helps you as well. My stats: iPhone 15 Pro Max running IOS 17.5.1, 2018 Honda CR-V EXL.
iPhone 15 Pro Max