gmc carplay issues with ios 18

I've seen quite a few complaints regarding problems with CarPlay specifically in GM vehicles. Seems to be tied to a particular model/version of the head unit/firmware.

First, try updating to 18.0.1 (released today). Nothing specific in the release notes about CarPlay, but it can't hurt. If that doesn't help, contact GM. Your head unit may need an update.

I’ve got an issue after updating to ios18 as well. 2023 GMC 3500HD, when connected to CarPlay my IMessage banners don’t show up while listening to music but they will pop up when on the actual CarPlay screen with all the icons. Used to work fine. Tried all possible combinations of settings but none made a difference.