If you Toyota Remote start via the App is not working, you may want your Toyota Dealer to check/follow these items. They will need access to your phone or have them add themselves as a guest. First make sure that parameter is even turned on via the Techstream and then follow the sheet instructions...
Also check and make sure that a new DCM was not just replaced because it will need to be activated.....
Also check and make sure that a new DCM was not just replaced because it will need to be activated.....