Why doesn't the app indicate 12V battery level?

If even one time. I've been left once or twice staring at a jump pack that read 100% a moment ago now reading 0% in less time than it took me to step from the engine bay to the door and reach in and try to start the car.

In my gen 3, I've now taken to disconnecting the battery cable (easy in gen 3, it's right there in the underhood fusebox) if I think the battery might be that drained, then making the car READY with the booster pack, then plugging the battery back in.

That's harder in gen 1 or 2, with no easy up-front way to disconnect the battery, have to get in the hatch. I don't know the story with the newer generations.

 

No doubt you've done all this but for others reading this thread and having doubts about their vehicles cellular connectivity (and has the initially free or subscription Drive Connect service) ...

Try using the "Hey Toyota" voice assistant liberally and ask how is the weather in "Moose Jaw". That'd certainly kick the vehicles cellular electronics into action whenever you have the feeling you're in a less than ideal location. The absence or speed of the reply might be quite telling.

And, maybe if you ever want to ratchet up Toyota's interest/involvement from their side with 12-v battery issues use the SOS button to summon their roadside assistance for a jump start. Of course, when you have your own booster you can cancel that request. But, if you do have time, let them incur some expense. At a minimum, it serves as another data point for you to assess whether the SOS conversation over the vehicles cellular connection at that moment sounds good and clear and connected. And, Toyota will no doubt have a record of when and where you called from. (and it seems from reply #8 that the cellular connection can possibly work even when there isn't enough power to start the vehicle ... that would be appropriate for an SOS service)

Finally, I found a couple pages from the Service Manual indicating that their Techstream system does log things related to the Data Connect Module (DCM). You'll see in the "System Operation Status Example" that it'll log occurrence time, whether roaming was on or off, if the vehicle was in a service area or not and what the strength of the cellular signal received by the vehicle was. No doubt, they can pull a report to coincide with the blocks of time you know you've had problems within recent history.



And, if desired, the best do-it-yourself log of when a 12-v battery might be experiencing drain or charging can be had with a bluetooth 12-v battery monitor that in my case records the voltage every 2 minutes 24x7. I've learned what happens when the DCM is involved or that darn EVAP pump kicks in for 10 minutes in the middle of the night when I haven't been near the car for hours. It all leads to discovery and learning and understanding.