The integration of the iPhone into the technical workings of your vehicle is taking a much more involved step than simply allowing you to access your media and apps through the dash.
The new Ambient Alerts system is going to act as a direct warning system for the health of your engine. When the iPhone with Ambient Alerts is positioned into a dock on the steering wheel it will act as a conduit to not just let you know that a problem is taking place, but to actually diagnose the issues and give you an indication as to how severe it is. Instead of just giving you a plain warning, which the car already does with the Check Engine light, the heart image can become different in appearance or even pulsate. How this will actually work in a practical setting remains to be seen, but it seems as though they are on the right track for this use of the iPhone as a way of assessing travel technologies.