We recently picked up our car from being serviced and now the mobile app doesn't work. We are getting the error message "mobile access disabled". How do we get the Tesla App working again?

Yes, the owner can tirn it on and off. I wish it had a PIN so the owner could control it ( not fir service but for kids).

Hit the controls button on the lower left corner. Then the settings button at the top. Then go to the "service and security" panel. Under "privacy" is the mobile access options. Turn it on.