CarPlay Reloaded

The wireless CarPlay was working great. Until it stopped. Did not stop completely, but started losing the connection, freezing, or not connecting at all. Interestingly, I installed the Ottocast wireless adapter exactly to solve similar problems with the wired USB connection. The hypothesis (never firmly verified) was that there was too high temperature-related clock oscillator drift in my Pioneer head unit: a cold iPhone would not connect to a sunbaked in-dash radio.

So the Ottocast solved the problem (perhaps by being equally "baked" with Summer sun rays and thus drifting the oscillator in the same direction, or simply by being less strict on USB timing, compared to the iPhone). That was Summer 2024. Come Autumn and Winter, and the stable configuration started behaving less stable. Freezing screen, erratic updates, not connecting at all, or disconnecting and reconnecting in a loop).

Of course the iPhone was the last suspect on the list. I was checking connectors, software / firmware updates from both Pioneer and Ottocast, nothing.

And just about when I really started to suspect the iPhone, the iOS 18.4.1 news rolled out. Suddenly it turned out I was not alone:

users of Apple’s CarPlay have been plagued by a series of bugs, crashes and all-round problems that have hampered the in-car entertainment system

It is hard to comprehend how such issues slip through (what must otherwise be very rigorous) release software testing at Apple. But on the other hand there are dozens of internal subsystems and components in an iPhone and probably the issue here was some sort of a race condition or a resource exhaustion.

iOS (as experienced on my iPhone 15) clearly suffers from low memory conditions. E.G, you cannot edit a screenshot (it just does not pop up when shot) or the camera fails to recognize a QR code (no green rectangle around the code) unless is killed and restarted. So it might have been the CarPlay was simply memory starved. Or something else, but we will probably never know.

The good news is it seems to be working much more stable now.