Hello Julis1957.
Thanks for reaching out to Apple Support Communities. We understand that turn-by-turn directions in your car with Maps no longer works since updating the iOS. We will be glad to assist.
Let's start by closing Maps on your iPhone and restarting to see if that helps.
Close an app on your iPhone or iPod touch
Restart your iPhone
Additionally, remove and reconnect your iPhone with your car.
To unpair a Bluetooth accessory, tap Settings > Bluetooth, find the device you want to unpair, and tap the info button , then Forget this Device. This will remove the accessory from the list of available Bluetooth devices.
To add the Bluetooth accessory to your device again, place it back in discovery mode and repeat the steps above to pair it.
How to connect your iPhone, iPad, or iPod touch to your car
If you need more help, Contact Apple for support and service
Cheers.