iPhone 15 on iOS 18.6.1 and 18.6.2 will no longer connect to my 2024 GMC HD Denali CarPlay!

I have restarted my iPhone multiple times, by holding the Up volume and side button simultaneously until I see the power off slider, but I will try the method you linked below.

I have completed the Forget process mutliple times, shutting off the vehicle, opening the door to allow it to go to sleep, etc. I have also rebooted the GMC infotainment after completing the Forget process, rebooting the iPhone also to really try to have a clean start.

My iPhone continues to connect to my wife's Grand Cherokee CarPlay without issues too. The fact that my service manager was able to connect right away with his iPhone is telling me that it's likely my iPhone that is the issue. Thank you -

Yes, wired does work but it hasn’t helped make the wireless CarPlay to function again. And yes, I could simply use the wired but I shouldn’t have to right? It’s so much more convenient to just leave the phone in my pocket. Thank you.

First of all, thank you for the time you are taking to help!

I have tried the forced reboot process (link). Then the process to connect with a USB cable. I then disconnected the cable and turned off my truck. On the next start up, I tried connecting wirelessly but it failed.

My wife got home from a business trip and I found her iPhone at version 18.6.1. Her phone connected immediately. Her phone will update to 18.6.2 tonight and I’ll try her phone again tomorrow.

If her phone connects on 18.6.2, that would indeed indicate an issue with my phone. This will be interesting. And if it does connect, then I’ll try the drastic step of wiping and resetting my phone to its original settings and complete a set up using my latest backup.

If her phone does not connect, then I’ll feel like it’s definitively a GMC issue. Thank you.

The plot thickens... My wife's iPhone (exact same model as mine) did update to 18.6.2 last night and connected without issue to my GMC CarPlay. This issue is on me, not GMC. I would guess that for me, the 18.6.1 update must have had an undiagnosed error, since that is when the trouble started in my timeline.

My next step will be a data backup and factory reset. I'm not looking forward to it, but it will have to be done regardless. I will report back afterward! Thank you.

Update: I backed up my iPhone and reset it. After the reset was complete, my iPhone 15 Pro Max still would not connect to my GMC CarPlay. It still only shows up as a bluetooth connected phone. As stated, my wife's iPhone is the exact same model, same age, same iOS version (18.6.2) and it connects to my GMC CarPlay seamlessly.

If that reset process wasn't drastic enough, I decided to take Verizon up on an offer to upgrade my device to an iPhone 16 Pro Max today. And NO, it will only connect to my GMC as a bluetooth phone. This is super frustrating and now points back to the GMC software and I'm betting that OnStar has something to do with it. Every time I call into OnStar to fix something, another function fails.

I'll call into OnStar next and report back again, if anyone cares...? Thank you.

SOLVED - A tech savvy GMC Service Manager finally figured it out: If your GM vehicle comes with an included OnStar data plan (like mine) or you are subscribing to an OnStar data plan, then you as the owner must connect to the vehicle's WiFi signal in order to connect to wireless CarPlay. This is why everyone else's iPhones will connect wirelessly to the car, because they are not enrolled in the OnStar data plan for said vehicle.

My GMC was connecting to my iPhone when I first got it, but after experiencing some trouble with OnStar and the included Hotspot, OnStar made some changes, and also had me make changes on my iPhone. One of tjhose changes made my iPhone disconnect from my GMC's WiFi and it was not set to Auto-Join.

As soon as the tech savvy service manager reconnected me to the GMC's WiFi, it all works as it should. I hope this has helped others that are experiencing similar issues! In addition, I called into OnStar 4 times for support since my CarPlay stopped working and no one from those support calls asked my about my connection to the GMC's WiFi.

No, I do not use a VPN on my iPhone. Thanks.

Another update: OnStar failed to fix this issue and has sent me to the dealership for service. My GMC is there now and I hope that they can find the issue.