The Definitive Guide to using a "Smartphone as a key"

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rxlawdude

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#1
(sorry for reposting this in a new thread, but don't want this to get lost for new owners)
Experiment #1: Samsung Galaxy S7 edge (my daily wireless phone)
Tesla App already installed and vehicles loaded into app.
Set to Airplane mode. This kills WiFi, Cellular, and BT.
While in Airplane mode, turned BT back on.

Result: All controls (lock/unlock, frunk and trunk) work while in proximity to the vehicle.
Experiment #2: Samsung Galaxy S7 edge. Rebooted phone while in airplane mode.
Opened Tesla app (of course, it says "check internet connection"). Cellular off, WiFi off, BT On.
Approach the vehicle.
Result: All controls (lock/unlock, frunk and trunk) work while in proximity to the vehicle.

Experiment #3: Verizon prepay Moto G Play (no account on Verizon, was used as an emergency phone for a 2016)
Used WiFi to go to Play Store, downloaded Tesla App.
While on WiFi, log into the app with Tesla credentials. Vehicles appear on app.
Turn off WiFi. (There is no cellular service on this phone!)
BT on.
App says "Set up phone to act as key? Have your keycard and go to the car." (paraphrasing)
Went to car. Followed app prompts.
Phone key success.

Result: All controls (lock/unlock, frunk and trunk) work while in proximity to the vehicle.

CONCLUSION: You DON'T NEED A CELL CONNECTION, OR EVEN A PHONE THAT HAS A WIRELESS ACCOUNT to use the phone as a "key."

However, if you want to use all the features of the app like climate and charging control, you (and the M3) must be in WiFi or Cellular coverage area.

Another caveat after playing with my junk pile of old phones. Android 4.3 phones (Galaxy S3) will NOT work because you won't find the Tesla app in the Android Play Store (which filters apps not compatible with the device you're on). Clearly, your phone can't be backlevel by more than a couple of major releases.
 
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SoFlaModel3

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#2
Wait... did you hard close the app and/or log out of the app in any of those tests though?
 

rxlawdude

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#3
Wait... did you hard close the app and/or log out of the app in any of those tests though?
Powering down the phone and bringing it back up isn't a hard close?
Obviously, after rebooting the phone, the app is not running. I have to open it.

But yes, SIGNING OUT REMOVES ALL VEHICLE DATA FROM THE PHONE. Don't do that! :)
 

arnis

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#6
Powering down the phone and bringing it back up isn't a hard close?
Obviously, after rebooting the phone, the app is not running. I have to open it.
Well, the service might run all the time. It's like Messenger app. You can close everything but notifications just come again.

Uninstalling (or disabling) app will have definite answer. Either Tesla app service is required or just BT pairing is enough.
 

rxlawdude

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#10
I have once again failed at reading comprehension. Thank you.
But the very next line was



So I don't think that answers the question about hard closing the app.
Why don't you provide specifics as to exactly what you mean? I contend powering the phone off and back on kills any active programs.
 

JWardell

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#11
I agree with @arnis : If you delete the app after successfully using it as a key, can you still unlock with Bluetooth? It should still be paired with the phone.
This would confirm whether the car actually needs to communicate with the app and its account data each time, or if once authenticated the car only needs to pair with a validated phone.
 

rxlawdude

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#13
I agree with @arnis : If you delete the app after successfully using it as a key, can you still unlock with Bluetooth? It should still be paired with the phone.
This would confirm whether the car actually needs to communicate with the app and its account data each time, or if once authenticated the car only needs to pair with a validated phone.
If you delete and reinstall the app and don't sign in, you will NOT be able to unlock.

You must have BT and the app with your car showing (meaning at least one connection to the Tesla mothership when signing in once with WiFi).

I believe Tesla has documented that signing out or uninstalling the app breaks the key function. That makes sense from a security standpoint.
 
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actong

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#14
Why don't you provide specifics as to exactly what you mean? I contend powering the phone off and back on kills any active programs.
Yes, but if you open the app again after rebooting, which seems to be what experiment#2 is implying, then the app is running again. Maybe I'm misunderstanding things, but I thought one of the questions was whether the car would unlock if the app wasn't running.
 

rxlawdude

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#16
Yes, but if you open the app again after rebooting, which seems to be what experiment#2 is implying, then the app is running again. Maybe I'm misunderstanding things, but I thought one of the questions was whether the car would unlock if the app wasn't running.
The answer is that without the app running, it will not work. Evidence: if app is "pointing" to my MS, the M3 does not wake up and does not unlock but the app is running! Similarly, if the app is not running (such as immediately upon reboot) the M3 will not respond.

And if you think about it, that's good security. Otherwise, there would not be a way for the M3 to "forget" a device you sell or give away.

So "key" = Tesla App running AND Tesla App "pointing to the M3 on screen," AND Bluetooth enabled.
 
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rxlawdude

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#17
Do the test again. But before approaching, disable temporarily Tesla app (do not log out, do not uninstall).
I don't believe you can "turn off" non-bundled apps. Your example is a built-in, bundled feature of Android, which cannot be uninstalled. Customer added apps such as the Tesla app will allow you to Force Stop or Uninstall. At least with Samsung Galaxy phones.