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phone key fails after upgrade

vanzandtj

Member
May 10, 2019
59
29
Nashua NH
Since the update to 2021-40 last week, my M3 doesn't recognize my phone as a key. I have to use the key card to drive (stepping on the brake brings up the "present the key card" animation). Walk-away locking fails too. The bluetooth connection to the audio works fine.

Navigating on the screen Quick Controls -> Locks shows two key cards (with edit icons) and my phone (without an edit icon).

I have an Android phone (Samsung Galaxy S7). I've switched it to airplane mode and back, and rebooted it.

Navigating on the phone Settings -> Connections -> Bluetooth shows "Tesla Model 3" under "Paired Devices". When I stand next to the car and touch that entry, it says something like "paired for media". I assume that's not related to the locks. Under "available devices" I see an 18 character string Sda...a6C. If I touch the latter, I get a message "Pairing rejected by Sda...a6C". Is that the connection for locking the car?

I restarted the screen, I think: I held both steering wheel buttons down, and after five seconds the screen went black. At about 85 seconds, the screen came back on with the same display as before. I never saw a Tesla logo. Is that what I should expect? Regardless, it didn't let the phone key work.

What should I try next?
 

vanzandtj

Member
May 10, 2019
59
29
Nashua NH
I tried deleting the phone key and restoring it. I got "Setup Failed. Please Try Again. Unable to set up your phone as a key for the vehicle", with a "Retry" button. The next time, I got "Finishing up. Verifying Phone Key pairing", then "Success. Phone key has been set up" with a "Finish" button. And it seemed to work for one short ride. However, when I sat down later with my foot on the brake, I got the "present the key card" animation again.

I have a theory: Tesla is using the Bluetooth mechanisms to recognize the phone (e.g. name and MAC address), but it is also making one or more analog measurements to "fingerprint" the Bluetooth hardware (as discussed in Bluetooth devices fingerprinting using low cost SDR and https://www.cse.msu.edu/~huangjun/docs/blueid_infocom14.pdf). If those measurements are not as accurate or repeatable as they think, or something shifts unexpectedly, then the phone may not be recognized. My phone is always in my pocket, but the Bluetooth hardware in the car may be temperature sensitive, and it's been getting cooler out. (I wonder whether women who keep their phones in purses have more trouble with the phone key function.) Or maybe that last software update changed the thresholds.
 

vanzandtj

Member
May 10, 2019
59
29
Nashua NH
When the car recognizes a phone as a key (not just that it's been set up, but also that the phone is currently nearby), is that status shown on the display somewhere? E.g. in the list of keys, should that line be highlighted or something?
Is the recognition indicated on the phone somehow? E.g. should the 18 character string be listed as "paired"? (I know the Tesla audio connection is shown as "paired", but that's an independent connection.)
 

vanzandtj

Member
May 10, 2019
59
29
Nashua NH
If the car is trying to fingerprint the phone, maybe it will just take several tries to get a good measurement. So I tried again on Friday. I did it in a parking lot, so the "unlock at home" setting wouldn't confuse things. I removed the phone key and reconfigured it with no trouble, and it worked - walk-away lock, walk-up unlock, drive away. But after the next stop I had to use the card key again.

Again today (Saturday), the car asked for the key card. I removed the phone key and reset it.
Walked away, it locked. Walked back, it unlocked.
Walked away, it locked. Walked back, it unlocked.
Walked away, it locked. Walked back, it unlocked.
Walked away, stayed away five minutes, walked back, it asked for the key card.

A key that doesn't even last five minutes is not worth much. What's going on?
 

Alset2

Member
Supporting Member
Feb 20, 2020
120
39
Ocala. Fl
This is now happening to my wife's 2020 M3. Same exact thing as OP right down to the reset procedure.
Very frustrating indeed. She has scheduled a service, hopefully others are experiencing this and they are aware of it prior to hers.

Ill post back when we hear something

BTW, got update 2021.40.6 late last night...all this has been going on all day today .
 

Jegga51

Banned
Nov 24, 2021
10
5
Iowa
Well 2 things to try, if you haven’t. 1) turn off the Bluetooth on your phone for several seconds and then back on. 2) do the 2-button with brakes applied reboot of your Tesla. I’ve had to do this recently, not sure if it’s my phone, iOS 13, or Tesla the latest Tesla software... but it hasn’t come back afterwards (yet).
 

Alset2

Member
Supporting Member
Feb 20, 2020
120
39
Ocala. Fl
Well 2 things to try, if you haven’t. 1) turn off the Bluetooth on your phone for several seconds and then back on. 2) do the 2-button with brakes applied reboot of your Tesla. I’ve had to do this recently, not sure if it’s my phone, iOS 13, or Tesla the latest Tesla software... but it hasn’t come back afterwards (yet).
Thanks for the response
I tried rebooting several times. Screen turns off after a few seconds like normal but then about 1 minute passes and the screen just pops back on like nothing happened. No logo , no hearing car shut down , none of the normal reboot stuff we are used to .
 

vanzandtj

Member
May 10, 2019
59
29
Nashua NH
I have an Android phone. On Nov 22, I updated the Tesla app (to version 4.3.0-472 or the like), and the phone key started working.
Then on Nov 24, I updated the phone app again, to 4.3.0-766, and it quit working.
Then on the same day the car updated to 2021.40.6, and it's been working ever since.

I am disappointed that they didn't maintain backward compatibility for even a short overlap interval.
I am more disappointed that neither the phone nor the car warned me of an incompatibility.
Tesla should by now have a more dependable update process.

By the way, to update apps on Android:
Open the Google Play Store app. Touch: profile icon -> Manage apps & device -> Update
 

clyde

Member
Jan 16, 2021
85
52
Cincinnati
Same issue on my 2021 M3P after update 2021.40.6.
Approaching the car and trying to open the doors or trunk with my hand or trying to start (with phone in pocket) will not work unless first activating the Tesla app on the phone. Then phone talks to Tesla and all is well, all the time. Whereas before the update I did not have to wake up my phone app to execute these functions, just have the phone close enough to the car.
 

Ashrafafandi

New Member
Jan 16, 2022
3
1
New York
My problem is a bit different. I tried to designate my phone as a priority device while on technical support with Tesla. Removed “Tesla model 3” from device list on phone & when reinstalled got a bunch of numbers & letters indicating car recognized my iphone 12 mini as key but not as bluetooth device. Problem is this bunch of letters& nos (phone is key) cannot be uninstalled as they don’t have the “i” at the end. After some extensive time wit Tesla & Apple & realizing wife's phone is perfectly working with the interface & car discover’s sun’s phone: models 12 & 11 respectively, elimination process screamed Apple. Spent a significant time with Apple on the phone Friday evening & now it has been escalated to software engineer. Keep fingers crossed: waiting for a call back from Apple on Tuesday & hopefully will report good news - aaah, the beauty of technology
 
is it Tesla or Apple related? maybe we need to open a ticket, my fitbit looses bluetooth connection, next to the phone too :(
So far, i have been working with Apple since Sunday. My wife’s phone has no problem & Tesla was able to recognize my son’s phone immediately, so elimination, Apple seemed to be the culprit. After installing a profile on my phone to collect info on bluetooth connecting & disconnecting to amass log on Tuesday, am supposed to hear from Apple’s software engineers this evening. Will post update as soon as that’s done. Tesla were v helpful & wouldn’t cancel my mobile appointment on Feb 3 despite it being fairly obvious it wasn’t a Tesla problem
 
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