I doubt this will ever happen, as CarPlay is designed to be safe while driving, and doesn't have visual things as basic as album art, let alone a bunch of info about a car's health.
Just seems like a logical thing. Safety features aside, knowing your cars health seems like a pretty big safety hazard not to know.
I was referring to CarPlay making it safer because it is supposed to reduce distractions, meaning keeping your eyes on the road more because there really isn't anything to do or look at. That's why there is very limited information given on any of the CarPlay apps.
I guess it could be a CarPlay app that is disabled while moving, and if there is a CEL or dash light, you can stop, put the parking brake on, and check the Car Health app to see what is going on with car.
Maybe it could keep track of maintenance, and give reminders during start up, or send notifications to your phone to check out later.
Again, I am not saying it is a bad idea, I just am skeptical that Apple will allow it. They won't even allow third-party navigation apps on CarPlay (an assumption). Also, I am not saying CarPlay is not useful, but it is one of their more boring, and overrated products imo.