Custom SIM card in Tesla Model 3 2024, Tesla Model Y 2025 and Cybertruck | Hacker News Reader

Custom SIM card in Tesla Model 3 2024, Tesla Model Y 2025 and Cybertruck

olegkutkov.me

60 pointsLorenDB33 comments

> Waking up the car The native Tesla mobile application wakes the car by sending an SMS to the internal SIM card number. This number is registered in the Tesla database. When using a custom external SIM, you must manually send an SMS (with arbitrary text) to your SIM number. Any SMS will wake up the car, and it will be available via the Tesla mobile app. Don’t forget to unsubscribe your SIM from any newsletters to avoid false wakeups and extra power drain.

Wow..

Does this mean spam sms could be waking up my car even without a sim swap?

If they did it right, these would be setup with their own range of numbers that can't be routed from anywhere outside of their carrier and servers.

Cell companies have a word for a setup like this but it escapes me.

Closed User Group (CUG)?

That's it!

Tesla has a custom APN

APN does not influence SMS (nor phone number routing) though.

Does it mean that if internal DB of internal numbers will be leaked anytime in the future, it will give to anyone power to wake up all Tesla cars in a few clicks?

Certainly sounds like it.

I think about this every time my car is slow to wake or doesn’t wake when in a spot with poor signal, it’s SMS fuckery.

Regardless of all their problems now, decisions like this that made Tesla successful. Need a low power always on way to send the car a signal to wake from a mobile device? Don’t invent and build some complicated hardware and protocol, just use SMS and a small cell phone board.

https://archive.is/svEad

Wonder if this could work with the Calyx sim now that they have BYOD.

As per the OP, there's no advantage of doing this if you're in a region that Tesla officially supports, because Tesla already has free connectivity with the free built-in SIM. The only use of this is if you're in a region where Tesla isn't supported, and thus Tesla won't have the necessary roaming agreements for its built-in SIM to work. The Calyx sim only supports US and Puerto Rico, so it's of no use. There's no privacy benefit either, because the phone can still upload your location/telemetry regardless of what SIM you're using.

Wouldn't this be relevant for those who want to decouple their car from Tesla tracking? Obviously only a partial solution, but still.

How are you decoupling from Tesla tracking by using your own SIM? The car has a built-in GPS so even if it can't track you by cell tower pings, it can upload your location to Tesla servers all day long.

I'm sorry did you miss the part where I said "obviously, only a partial solution"?

It's unclear whether Tesla even does any tracking through the cellular connection, when it can get far better accuracy through the GPS receiver and myriad of cameras/sensors in the car itself.

Maybe I misunderstood and assumed this would allow premium connectivity as Tesla is no longer footing the data bill. But if that’s not the case then ya it’s kinda pointless.

Why they didn’t use eSIM?

I flagged this because the site runs some Javascript for me that attempts a redirect to a spam page (which uBlock caught). Looks like there might be some malicious code injected there.

I can't reproduce that.

Ditto. Viewed it just fine via Safari on iOS. I'm guessing GP accidentally triggered the form for the comment system.

Try with a Russian IP.

No thank you, I have all of Russia/China/Belarus's normal IP space blocked at the router in both directions. I don't expect it will protect me from anything, but it's a great way to not accidentally step into bullshit.

I can reproduce this. It might be only happening for Russian IPs because it does not happen if I use my VPN.

(The author is Ukrainian, so nothing surprises me at this point)

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