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

I assume you are talking about the Toyota app that connects to the car. I agree that a look at the actual 12v battery voltage would be a nice feature. Any questions about why it is not included in the app would need to be directed to Toyota. Maybe if enough people ask for it, Toyota will include it in the future.

 

good idea

 

So, you want hardware and software running all the time to monitor battery state and communicate that info to the Toyota servers using the data communication module? And this is because you're concerned about the car using too much power when it's not in use?

Does anyone else see the inherent problem with this idea?


OP: Just have your battery tested again so that they'll tell you it's bad, you'll get a replacement under warranty, and we can put this to bed for a few months. Please?

 

If the idea is to know in advance whether the battery level is too low to do anything perhaps using the Toyota app might work as is.

At the bottom of the "Status" tab it'll indicate how many minutes since the data has been updated. If not current, you can then pull down on your screen or click the refresh icon and that'll command Toyota to communicate with your vehicle and grab the latest data.

Seeing anything other than just now or less than a minute ago but rather an "Updated: x minutes ago" that only climbs might be indicative of boost-pack time again.

And as @Hammersmith indicates there's a cost to your 12-volt battery just doing these refreshes and not something you'd want to just do over and over in a single session. Somehow I think Toyota knows this or has agreements with mobile carriers to perhaps limit the number of times one can refresh in a given period of time.

 

The Toyota app does not work like you described. Forcing a refresh at the bottom of the status screen does not "command Toyota to communicate with your vehicle and grab the latest data". The refresh only causes your Toyota app to connect to the server and refreshes the data on your app from the data on the server. It does not force a connection from the server to the car to grab the latest data from the car.

You may ask, how I know this. I have the Toyota app connected to my 2026 Toyota. On the status page, I see the diagram of the car showing the four tire pressures. Just below that, it says,
Tire Pressure
it shows a blue check mark and Good
Updated 19 hours ago

The information on the status page does not change when I force a refresh at the bottom of the status page.

So, the Toyota app can not be used to force a connection between the car and the server. The app can not be used in the way you described to check to see if the 12v battery level is too low to do anything.

 

You are correct. See my post #9 for an explanation.

 

Yes, I agree with you about the tire pressures not updating when refreshing the app as those TPMS sensors only wake up when the wheels physically move to preserve the battery in each sensor and even then their tiny batteries probably throttle their updates less often than right this minute. But still kind of know from my own experience that other stale data in the app is updated after Toyota reaches out and consults the vehicle ... door locks, windows are kind of important to know the status of remotely at times and perhaps even the HV/Traction battery charge level.

 

Well some Kia/Hyundai vehicles have "solved" the issue along the lines you describe by including a 12-v battery reset button on the dash. They can get into their dead vehicles with the physical key and just press that reset button and it'll briefly allow access to the high-voltage hybrid battery and let them attempt to start the vehicle. Of course, they too still have to reset all those settings that get lost when the 12-v system died (probably why they call it a reset button). And, naturally, once started their 12-v battery must be charged again by the same systems that take care of doing that by keeping it on and in a ready state 30-minutes.

 

You are correct. Please disregard everything I wrote in post #9.

I did a little experiment on my car. I opened one of the rear door windows. I had that door unlocked. All three of the other doors are locked. I refreshed the Toyota app data. It showed the windows open and doors unlocked. I waited a few minutes, then reached through the open windows and locked the door. I waited a few minutes and refreshed the app. The app then showed the doors as locked. So refreshing the app does cause the server to connect to the car and update the data. Thank you for bringing this to my attention.

 

At this point, are you still focused on identifying a single root cause, or more on workarounds and practical ways to keep the car usable day to day? It reminds me a bit of a tire that keeps losing air—repeated reinflation works short-term, but it usually means there’s still an underlying leak that hasn’t been fully located.

 

That’s working for me too, albeit with a ‘10. If practical, just leaving it connected pretty much constantly works well. I put in a fresh battery (Optima Yellow Top) in September of 2015, and it’s still load testing like new, voltage the morning after a drive around 12.8~12.9.

garage stored and having quick-connect cable installed helps.