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Pulse Ox not working + Heart Rate not working when Pulse Ox is turned on


Got my 945 yesterday and set it up. Everything seemed to be working fine initially.

During the evening I went through some settings and turned on HRV Logging, Sleep/All-Day Pulse Ox, etc.

After this I noticed all heart rate data started displaying "--" with maybe one value every few minutes at best before going back to "--". Stress measurement started showing "Check watch fit" when trying to do a measurement and I was unable to get a single Pulse Ox reading during the whole evening. I went to sleep thinking it might just need some time to adjust.

I woke up with absolutely no sleep data or HR data for the night. After not getting more than a few blips of wrist heart rate data all morning regardless of restarts, different clock position on wrist, band tightness or even wrist side, I went back into the settings and tried turning off the Pulse Ox sensor. After this the heart rate reading updates reliably every few second and everything seems to work again.

I have now tried this multiple times to make sure. Turning on Pulse Ox in the Sensors menu makes all wrist heart rate measurements disappear and turning it off makes them work like normal again. No Pulse Ox readings have been captured at any point and can't be captured manually either.

Anyone have any info on this? Some known software issue, a faulty sensor, something else?

Software version 2.60 (2fa11e6). (EDIT: upgrading to 2.64 beta or downgrading to 2.50 does not help. Neither did 2.70.)

Lights on the back of the watch seem to work quite differently when Pulse Ox is on, cycling through a blink pattern if that is of any value, but I have nothing to compare to. (EDIT: took a video of it since it looks like the sensor in an endless reset loop: Local Garmin support said it does not look like what their test unit looks like)


  • All manufacturers have issues, the key is how you deal with them. I expect the overwhelming number of people here would be happier if Garmin would more openly acknowledge and issue, even if it said it would be some time before they resolved it.

  • Former Member
    0 Former Member over 4 years ago

    Is this really such an issue that people are going to return their watch or never buy Garmin again?  What are you using PulseOx for anyway?  It measures how oxygen is saturated in the blood at higher altitudes. OK, you got a reading. Now what? It's not even a precise measurement and doesn't factor in to any of Garmin's/Firstbeat's metrics.  If turned on continously or during sleep there are problems. Turn it off until fixed.  You can select the widget anytime you want a reading and it saves battery. It's such a small issue I find it difficult calling it even minor.  Some of you are posting as if the watch is now useless. 

  • I'm asking myself the same questions.

    Do you all NEED PulseOx to work, or do you just want it to work because it's part of the features and you "paid for it"? I mean yes it's a defect but it's not like if HRM was not working at all...

    It's not working on my watch, but I really don't need it so it's turned off, waiting for a fix, but I would love to hear why you guys need this metric so much ?

  • Got an upgrade to software version 2.8 - Pulse OX is working right now, that didn't work before.

    But HR stops working as soon as I switch Pulse OX on

  • Within widget Health stats, I have a sub-widget of Pulse Ox which  has always show me "no data" does that mean pulse Ox is not working for me (I am not concerned yet, as learning the rest of the watch....)

  • If you have not chosen 'all day' or 'sleep' recording of Pulse Ox, and have not stayed on the Pulse Ox widget for it to take a manual recording, it has no data to display.

  • I paid 599euro and I m expecting all features to work OK

  • Former Member
    0 Former Member over 4 years ago in reply to TehesFR

    It´s like buying a new car and the air-con doesn't work.

    Yeah I can drive it but is it bothering me? Yes!

  • Same to me!, tomorrow I'll do it!, the only problem seems I'll receive a new one in black color instead the blue I have it.


  • Do not buy it I am very disappointed from Garmin support and warranty