Funny, my phone can provide accurate routing data with out the car. What data from the car does the phone need to be able to accurately route? I'm at my desk no where near my car and it is working just fine
Current battery level and consumption, so that it can tell you whether you will make it to your destination with adequate charge left or insert charging stops where needed.
Today this is done via an OBD Bluetooth adapter or via CarPlay/Android Auto APIs that allow the phone to get data from the car.