I have asked this before without a definitive answer. My 23 Z51 is in a remote winter storage. If something happens to my tender ( power out, unplugged , failure etc. ) will the My Chevy app notify me if voltage gets too low ?

 

anybody?

 

Highly unlikely. I've never seen anybody comment that they have gotten such a notice.

 

Yes... if you have OnStar activated it will send a notice as the car wakes up periodically to do a status check.

 

Thank you very much Rapid !

 

I think its hit or miss…., I took the entire battery out of my car for a week and I didn’t get any notice from OnStar nor the app…

 

Because the car and onStar were dead with no power.

 

then the car should tell you that basically they’re not receiving data from it anymore. I never got that either

 

If in a garage , OnStar can't communicate with the vehicle unless you pull the vehicle outside.. So there is that...

 

That's not true. If your cell phone works in your garage, OnStar will too. OnStar uses cellular for voice and data with better antennas than your cell phone has, so it can get a signal when your phone can't (all this assumes your cell phone and OnStar are on the same cellular network or at least networks with similar coverage). OnStar uses AT&T cellular. OnStar uses satellite for GPS data.

 

To add to that, if you allow our car to connect to your internet enable WiFi in your garage, as I have, OnStar can also communicate with OnStar via that path. It can even receive OTA downloads vai that path.

Pretty sure I have seen reports of members receiving a Low Battery notification. But I do not believe they are reliable even if the occur. The reason I say that is because for the majority of reports of a suddenly dead battery issue, I cannot recall anyone saying the got a notification from OnStar before it happened.

 

Many seem to be under the misconception that the car communicates via satellite. It does not. It only receives signals from GPS satellites to determine location data. There is no "up-link" to GPS or any other satellite.

 

My Chevrolet app says last connected 5 days ago. Since it has been in storage for 2 weeks I am assuming it is still able to communicate from that location. Also if I activate map it shows the cars correct location !

 

Mine does for sure - but mine can connect to the WiFi in my garage. I don't put it in storage, but if the weather is not good, or there is salt on the roads, it can sit for a couple of weeks or more in my garage. My garage is heated, but I let the temps drop to maybe between 40 and 50 if I am not working in there. I have had the tire pressure drop in cold weather to the point where I received an alert about it (not recently). But it proves that it connects and communicates. There is a specific function for that actually. When the vehicle is stationary, the TPMS internal shock sensor is inactive which puts the TPMS into a Stationary state. In this state the sensors sample tire pressure once every 30 sec and do not transmit at all if the tire pressure does not change. The TPMS will transmit an Alert if a 1.2 PSI change in tire pressure has been detected. And the car will transmit an alert to OnStar when it connect if the pressure drops too much. I do not know whether it connects whenever it detects a tire pressure issue, or if wakes periodically and transmit whatever alerts are active at that time. I do know (from service manual descriptions) that when the TPMS transmits, the car wakes up enough to receive it (a spike in parasitic draw according to the manaul) and I do know that some other modules wake up periodically and then go back to sleep.

 

I would never get an OnStar vehicle report until after I pulled the car out of the garage. Why is that? I could start the car numerous times in the garage and not pull out and never get a report. Strange.

 

I think that means two things: 1) its not connected to a WiFi, and 2) for whatever reason its not able to connect to the 4G network while it is in your garage. The antennas for it are located under both the left and right front fenders toward the front. Its normally really really difficult to prevent that car from connecting. There are long threads where folks have attempted to disable OnStar by totally disconnecting the antennas - but even then if the signal is strong enough it seems to sneak through. I don't recall if anyone ever successfully fully disabled it that way.

 

Post #12 taken from OnStar shows how OnStar works. Communication (other than GPS) are via cellular network. Unless you live in a poor AT&T coverage area, cellular should work in your garage. OnStar has better antennas than cell phones do, so it sometimes works where cellphones won't. I can definitely press the blue OnStar button while in my garage and talk to OnStar.

 

The 2023 model year comes with a 3 year Onstar plan. Depending on when yours was built that plan including diagnostic notification may be ending in the coming months, or already did if from early in the model year. Unless of course you pay to extend the diagnostics plan option.

 

My 2021 is over 4 years years old. It had a short trial (1 month or three months) and I never activated any follow on subscription. I still get the diagnostic information. The latest was the November report received via email on 11/26/2025. This reports show oil life, tire pressure, and the status OnStar, AirBag, ABS, Emission System, Stabilitrak, Engine and Transmission, along with some other information.

The last time I received an alert of an issue outside of the normal diagnostic reports was March of 2022 and at that time the car was at least 9 months old, well beyond the trial period. That alert was received by email and notified me of low front passenger side tire. The car was off, in my garage, and I was experimenting with the tire fill alert system by letting air out and then adding air to see if it behaved as described in the manual with flashing turn signal and beeping horn. It did, and I reinflated the tire to the proper pressure. The car was never turned on. When I got back to the house, I already had that alert in my in-box. It must have been sent withing minutes of the low pressure condition I created when I let air out.

 

You are still supposed to get monthly diagnostic reports but real time only comes with a paid plan, or so they say.