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My S6's altimeter glitched out, putting me at about 8000 ft higher than actual elevation

tzm41

macrumors 6502
Original poster
Jul 11, 2014
316
864
Boston
So I have spent the past month going back and forth with Apple trying to solve this weird issue on my Apple Watch Series 6 cellular model, which started happening since I moved from NYC to the Bay Area:

IMG_7785.jpeg
IMG_7786.jpeg

As the screenshots show, my watch puts me about 8000 ft higher than what my phone tells me. I tried resetting the watch, which would initially fix it. However it does go back to reporting the wrong elevation after I do an outdoor workout. Relative elevation gain is correct, but the absolute value goes absolutely crazy. This is what happens when I do the first outdoor workout after resetting the watch:

IMG_7787.jpeg


1. I started calling Apple about a month ago, and the support advisors promised that he would have someone on the health support team call me but that never happened.
2. A week later and the third time I called Apple, I finally got to a health support specialist who has been helping me since then. She first collected diagnostics and logs and sent my situation over to "Apple engineers", who then determined that it is a hardware issue.
3. I sent the watch in for service, but they claimed not being able to reproduce the issue, hence sent my watch back unfixed.
4. So I reproduced the issue, called the same specialist again, who told me to send it in again, and she will attach a special note to it. Yet, Apple sent my watch back unfixed stating the same reason.

This frustrating process has taken three weeks and counting. So it looks like a hardware issue, until I decided to do some experiments myself since Apple isn't competent enough to figure out what is wrong.

1. Let's say my original watch is watch A. I bought an Apple Watch SE GPS (B), and another Apple Watch S6 cellular (C). I paired them to my iPhone and took them to outdoor workouts.
2. Interestingly watch B's altimeter remained accurate after a long hike, but after a brief outdoor walk watch C's altimeter also started to be off by 8000 ft.
3. Suspecting that it might somehow be related to the cellular functionality, I then reset watch A, and then did an outdoor walk without adding the cellular plan to it. No glitch.
4. Then I moved the plan over from C to A and then did another outdoor walk. Now it is glitched again.

So now I am much less sure that it is a hardware issue, since the chance that both watches A and C are faulty in the same way is probably low. But I also couldn't figure out why it started happening after I moved to the Bay Area, not can I accept an 8000 ft error on my Apple Watch, or just give up the cellular functionality. Any chance someone can give me advices on what is going on?
 

waw74

macrumors 68040
May 27, 2008
3,887
506
does it only happen at home?
how close to home are you working out?

This is a wild guess, and I have little to no knowledge of how cell works. but...
there is location information imbedded in cell signals, it's possible a tower by your house is configured wrong. doesn't explain why it's only the watch though. Although maybe it also has to do with type of signal (LTE, 3G) and your watch is on one while the phone is on the other.
I believe the watch uses a combo of "electronic" location to help keep the barometric altimeter calibrated, since weather changes can affect it.

wifi can also used to help with location, that's done with an external database of the Mac address of wifi routers and their coordinates. You can get the MAC address of wifi networks without joining them. You phone will connect to a server and says what MACs it can see, and the server will reply with a location.
Not sure if this has anything to do with it.

if you reboot the watch when you're away from home does it sort itself out?
you probably want to be at least a mile or 2 away, and have the phone off or in airplane mode.

also explains why it might not fail when it's in the shop.
 
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tzm41

macrumors 6502
Original poster
Jul 11, 2014
316
864
Boston
does it only happen at home?
how close to home are you working out?

This is a wild guess, and I have little to no knowledge of how cell works. but...
there is location information imbedded in cell signals, it's possible a tower by your house is configured wrong. doesn't explain why it's only the watch though. Although maybe it also has to do with type of signal (LTE, 3G) and your watch is on one while the phone is on the other.
I believe the watch uses a combo of "electronic" location to help keep the barometric altimeter calibrated, since weather changes can affect it.

wifi can also used to help with location, that's done with an external database of the Mac address of wifi routers and their coordinates. You can get the MAC address of wifi networks without joining them. You phone will connect to a server and says what MACs it can see, and the server will reply with a location.
Not sure if this has anything to do with it.

if you reboot the watch when you're away from home does it sort itself out?
you probably want to be at least a mile or 2 away, and have the phone off or in airplane mode.

also explains why it might not fail when it's in the shop.
I’ve suspected the same. However, there was once when I reset the watch without doing the first workout near my home. The glitch appeared when I did a hike in the mountains. The workout summary shows a low of 341 and high of 9117 ft.

The mountains were about 15 miles away from my home. So it might not be specific to a cell tower near my home.
 
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jkel777

macrumors 6502a
May 10, 2014
528
81
I’ve had issues with my altimeter since February 8th. It does not record any elevation data during outdoor runs and walks. Elevation also just shows dashes in the compass app on the watch. I have tried everything except restoring my iPhone and sending the watch in for repair. I think it’s software related because the My Altitude app shows elevation on the watch just fine. Anyone have any experience with this or solutions? It randomly worked yesterday for most of the day but then stopped working again in the evening.
 
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tzm41

macrumors 6502
Original poster
Jul 11, 2014
316
864
Boston
I’ve had issues with my altimeter since February 8th. It does not record any elevation data during outdoor runs and walks. Elevation also just shows dashes in the compass app on the watch. I have tried everything except restoring my iPhone and sending the watch in for repair. I think it’s software related because the My Altitude app shows elevation on the watch just fine. Anyone have any experience with this or solutions? It randomly worked yesterday for most of the day but then stopped working again in the evening.
S6 or SE?
 
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jkel777

macrumors 6502a
May 10, 2014
528
81
S6 or SE?
Series 6 cellular. I’ve done everything from turning location services off and on, fitness tracking off and on, unpaired the watch and restored from backup, unpaired the watch and set up as new, reset fitness calibration, and still doesn’t work.
 
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tzm41

macrumors 6502
Original poster
Jul 11, 2014
316
864
Boston
Series 6 cellular. I’ve done everything from turning location services off and on, fitness tracking off and on, unpaired the watch and restored from backup, unpaired the watch and set up as new, reset fitness calibration, and still doesn’t work.
Ok maybe try Apple support then. Cellular watches are the ones giving me issues so maybe more exposure to them would mean some sort of fix...
 
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jkel777

macrumors 6502a
May 10, 2014
528
81
Ok maybe try Apple support then. Cellular watches are the ones giving me issues so maybe more exposure to them would mean some sort of fix...
I did and they weren’t much help unfortunately lol. Guess I’ll just see if it fixes itself.
 
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tzm41

macrumors 6502
Original poster
Jul 11, 2014
316
864
Boston
I did and they weren’t much help unfortunately lol. Guess I’ll just see if it fixes itself.
Understandable. I’ve been in back and forth with them for over a month without any fix.
 
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jkel777

macrumors 6502a
May 10, 2014
528
81
Understandable. I’ve been in back and forth with them for over a month without any fix.
Yep I’m not sure what caused this issue. Everything was fine up until the 8th. I’ve read elsewhere that it fixes itself which was the case for me for a day at least.
 
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Cheefy

macrumors member
Dec 27, 2020
73
34
When I first got my AW6 in December, the altimeter readings were way off. After several conversations on here and with Apple Support, it sorted itself out after a couple of weeks of GPS activities. It was then extremely accurate. About four weeks ago I reset my watch for a different reason and when I re-paired it, the elevation was back to being inaccurate again. After another week or so of GPS activities it returned to being very accurate again. From “as new” status it seems to need a period of calibration or artificial learning. When it goes through this and the accuracy sorts itself out, my watch is more accurate than either of my Garmin watches and any of the non Apple watches of the pals I run with.
 
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michaelb5000

macrumors regular
Sep 23, 2015
161
84
If you install an app that uses elevation or the altimeter, so Workoutdoors or an altimeter app like UpHigh or Altimeter+, what values does that show for elevation? Try that when you don't have the phone with you or the phone is off. We have discussed here previously that the altimeter complication as shown there in the compass app shows incorrect values at times, but the watch actually does know your correct elevation and apps that use that will show correct values.

It is also possible that the barometric sensor is broken on the watch (that has happened to some users here over the years, since watches have had that sensor before the S6).
 
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tzm41

macrumors 6502
Original poster
Jul 11, 2014
316
864
Boston
When I first got my AW6 in December, the altimeter readings were way off. After several conversations on here and with Apple Support, it sorted itself out after a couple of weeks of GPS activities. It was then extremely accurate. About four weeks ago I reset my watch for a different reason and when I re-paired it, the elevation was back to being inaccurate again. After another week or so of GPS activities it returned to being very accurate again. From “as new” status it seems to need a period of calibration or artificial learning. When it goes through this and the accuracy sorts itself out, my watch is more accurate than either of my Garmin watches and any of the non Apple watches of the pals I run with.
Interesting, my watch went from accurate to extremely inaccurate....
 
Comment

tzm41

macrumors 6502
Original poster
Jul 11, 2014
316
864
Boston
If you install an app that uses elevation or the altimeter, so Workoutdoors or an altimeter app like UpHigh or Altimeter+, what values does that show for elevation? Try that when you don't have the phone with you or the phone is off. We have discussed here previously that the altimeter complication as shown there in the compass app shows incorrect values at times, but the watch actually does know your correct elevation and apps that use that will show correct values.

It is also possible that the barometric sensor is broken on the watch (that has happened to some users here over the years, since watches have had that sensor before the S6).
The workouts recorded using the built in workout app show incorrect altimeter as well, not just the compass app. I just tried Altimeter+, which shows a dash and forces me to calibrate it with a number, so I input the number shown on my phone and it displays that number. Although the compass app still shows the wrong number. I’ll do another workout without my phone to see what happens.
 
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