To update the actual Android software: 1)From your home screen press the "Menu" button (left hand button on phone below screen) 2)Press "Settings" 3) Scroll to the bottom and press "About phone" 4)Press "System updates" 5)Follow prompts if it finds anything.
To update apps, either wait to be notified about them and click the notification to update, or: 1)Open Android Market on phone 2)Press the "Menu" button 3)Select "My Apps" 4)Select "Update" if any updates are available. If they are not, it will just show a list of installed apps.
If your Android Auto keeps disconnecting immediately or randomly, maybe this will help
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