I missed my plug in reminder email Friday night and saw the EV System warning indicator when I started the car yesterday. The indicator did not clear after cycling power to the car so I checked DTCs and found the usual EV System Incomplete Shutdown along with a few others related to CAN Bus communication. There was also a code related to the TCU antenna. I had the TCU upgrade done last December and have needed to reset the TCU a total of 5 or 6 times both before and after replacing the 12-volt battery. In all cases, the EV System warning light came on when starting the car after failing to receive a message the car should have sent (such as plug in reminder or charge complete notifications). I now believe the EV System Incomplete Shutdown and other DTCs occur after the TCU is unable to send its text message through ATT (regardless of the status of Nissan's servers). There would have been more incidents if it were related to Nissan's servers and only 1 or 2 incidents if it were due to low auxiliary battery voltage.
I pulled the 20-ampere fuse yesterday to reset the TCU, accepted data transmission in the CarWings menus, and it has been transmitting messages normally. It also updates charging stations and responds to remote status update requests quickly.
I pulled the 20-ampere fuse yesterday to reset the TCU, accepted data transmission in the CarWings menus, and it has been transmitting messages normally. It also updates charging stations and responds to remote status update requests quickly.