Garmin Edge 840 keeps on losing sensor connections

[NotShatterProof]

I have an 830 with the same problem. I ride with a Varia, Quarq and HRM Pro. As a minimum it happens once every ride, most times more than once: all sensors are disconnected. Considering that I commute a fair distance daily, that is a lot of crashes. Fortunately, in my case, within about a minute the software seems to recover and reconnect the sensors; not always though, on the odd occassion only a reset will work. Annoyingly the Varia often changes from flashing to solid mode after a crash, which is not optimal if you don't notice it.

Considering the rain we've had here in the last while I can say that the fact that the touchscreen lock does not work consistently and causes weird display issues is my top grievance at the moment. 

I've kept all firmware updated to the latest at all times, the latest firmware seems to have exarcerbated the problem but that is hard to quantify.

None of the above solves the problem of course but at least now I know I'm not the only one...

[Dexter-morgan]

I think I have won the Garmin lotto, I have had a number of garmin products with only one issue, I bought a FR205 with Zero issues, then I bought a FR225 "unboxed" from Garmin when they still did the unboxed deals, it failed within 6 months, that was replaced by a FR235, I had that for around 2 years sold it bought a Vivoactive 4, after 2 years, I bought a FR965, still have it, all of the watches with Zero issues, Not even mentioning my Edges, I had an Edge 500, then got a 810, sold it got a 520, sold it and got a 530 on a Evans cycles Black Friday special, passed that onto my wife and I now have an Edge 540, all with Zero issues.

My only problem so far is the heart rate straps, I use a very old wahoo strap with a Garmin pod - as I said I think I won the Garmin Lotto.

[ChrisF]

3 hours ago, Dexter-morgan said:

I think I have won the Garmin lotto, I have had a number of garmin products with only one issue, I bought a FR205 with Zero issues, then I bought a FR225 "unboxed" from Garmin when they still did the unboxed deals, it failed within 6 months, that was replaced by a FR235, I had that for around 2 years sold it bought a Vivoactive 4, after 2 years, I bought a FR965, still have it, all of the watches with Zero issues, Not even mentioning my Edges, I had an Edge 500, then got a 810, sold it got a 520, sold it and got a 530 on a Evans cycles Black Friday special, passed that onto my wife and I now have an Edge 540, all with Zero issues.

My only problem so far is the heart rate straps, I use a very old wahoo strap with a Garmin pod - as I said I think I won the Garmin Lotto.

 

Similar experience

 

My FR35 went wonky, and was promptly replaced.

 

The 530 was physical damage, certainly not a Garmin issue.

 

Touch wood

[Skubarra]

3 hours ago, Dexter-morgan said:

I think I have won the Garmin lotto, I have had a number of garmin products with only one issue, I bought a FR205 with Zero issues, then I bought a FR225 "unboxed" from Garmin when they still did the unboxed deals, it failed within 6 months, that was replaced by a FR235, I had that for around 2 years sold it bought a Vivoactive 4, after 2 years, I bought a FR965, still have it, all of the watches with Zero issues, Not even mentioning my Edges, I had an Edge 500, then got a 810, sold it got a 520, sold it and got a 530 on a Evans cycles Black Friday special, passed that onto my wife and I now have an Edge 540, all with Zero issues.

My only problem so far is the heart rate straps, I use a very old wahoo strap with a Garmin pod - as I said I think I won the Garmin Lotto.

500 was bulletproof - had it many years, currently happy with my 530 - no issues

520 was a disaster for me, worked through 3 of them in 2 years, had the weirdest random issues, each of them basically only lasted 6 months. Made me invest in a cheap Xoss so that I have a cycling computer while Garmin took their time responding to my issues.

[SCD]

28 minutes ago, ChrisF said:

 

Similar experience

 

My FR35 went wonky, and was promptly replaced.

 

The 530 was physical damage, certainly not a Garmin issue.

 

Touch wood

Ok, good to hear.

I sent my first query via their support system a week ago and did not receive a response yet. It doesn't feel good to feel so ignored. Maybe Garmin is coming to the CTCT Expo. I will take my 840 have them 'fix it' in front of as many potential customers as possible. 

[SCD]

18 hours ago, ChrisF said:

 

Worth speaking to them, but I do believe they only handle items bought from them.

 

Sadly you are down to sending it to Garmin yourself ...... and waaaaaaiting those three weeks, then a few more emails.  Couple of Hubbers do have the right email addresses .... @Johnny82

 

And then the lottery of how they want to deal with it.

Thanks for the contact.
@Johnny82 : could you please the 'right' email addresses with me?

[Johnny82]

23 minutes ago, SCD said:

Thanks for the contact.
@Johnny82 : could you please the 'right' email addresses with me?

Sure, I responded to your PM but don't mind sharing the addresses here too:

 

These are the email addresses I used, you get read receipts but with very little else in response. It is quite frustrating

productsupport@garmin.com

crmatlas.2@garmin.com

gsainfo@garmin.com

morne.smith@garmin.com

[Kom]

On 3/4/2025 at 8:35 AM, badiejb said:

I have both of these units. I am planning on doing a comparison next week between these and the wahoo. Stay tuned. 

i think hammerhead are way ahead on interface. and recently been playing with the integration of epic ride weather directly onto the computer can now see current and upcoming wind direction during a ride. also must say that komoot for finding routes and direct integration to the computer is also a win.

i would not go touring with a garmin or a wahoo elemnt - their interfaces and intuition are terrible.

i will still only use wahoo for racing conditions - still the best in class for reliability, power, elevation data and accuracy.

[cadenceblur]

Thread revival

Had the misfortune of having similar issues with Edge 840 today…

lost connection to my power meter and varia but strangely not to my HRM (dual)

It intermittently and repeatedly lost and regained connection over about an hour or so, then just refused to find my PM , 

Later in the ride , everything worked 100%
Talk about frustrating. I was not able to reset during the ride though. 
 

I hope this was just a blip…

[JoeMerida]

If the Battery is More than a couple years old and weak You get Bluetooth and Ant+ Disconnects on most Garmin Products (Watches and Headunits). Usually a Bad Battery will Charge quite quickly to 100 % but Drop to +- 83 % pretty Quickly. Bluetooth seems to go first but eventually Ant + will get weak as well.

[cadenceblur]

6 minutes ago, JoeMerida said:

If the Battery is More than a couple years old and weak You get Bluetooth and Ant+ Disconnects on most Garmin Products (Watches and Headunits). Usually a Bad Battery will Charge quite quickly to 100 % but Drop to +- 83 % pretty Quickly. Bluetooth seems to go first but eventually Ant + will get weak as well.

Battery seems fine, I did a 4:30 rode today and from 100% it’s now at 79%
it also only gets charged once a week before my weekend longer rides , 

[NotSoBigBen]

I have an older 520 with similar problems, every so often while riding it'll disconnect from my phone and reconnect then disconnect and reconnect the ANT+ HR and PM. Stats are all OK after the very short disconnect/reconnect. Problem is the livetracking then stops and doesn't restart and no auto upload at the end of the ride. I switch it off and on after the ride then the upload works ....

I just live with it, nothing that affects my riding enjoyment 😉 

I have an 810 and 820 that don't have these issues, both the batteries are not great. The 820 I use for short rides and the 810 for long or rides where I need navigation then I just use a power bank

[cadenceblur]

2 hours ago, NotSoBigBen said:

I have an older 520 with similar problems, every so often while riding it'll disconnect from my phone and reconnect then disconnect and reconnect the ANT+ HR and PM. Stats are all OK after the very short disconnect/reconnect. Problem is the livetracking then stops and doesn't restart and no auto upload at the end of the ride. I switch it off and on after the ride then the upload works ....

I just live with it, nothing that affects my riding enjoyment 😉 

I have an 810 and 820 that don't have these issues, both the batteries are not great. The 820 I use for short rides and the 810 for long or rides where I need navigation then I just use a power bank

Yeah, my data for today was completely messed up, as you can see from pics the outage was for a long period and even worse on an ascent ! 

[RaptyrOne]

Same... new Garmin Edge 840. Last week my Assioma MX2 pedals dropped out while all other sensors including Varia Radar and HRM stayed online. Not the first time it has happened. Stopped getting cadence and power readings on the unit screen. Went into the Sensors menu and reconnected the sensor and all was well for the rest of the ride. On the next ride the Garmin Radar dropped out for a while but then automatically reconnected. Seems random but it is annoying when these disconnects happen. Running the latest software/firmware. Seems Garmin has a few bugs that need to be squished. They make aviation instruments, so you would think they would be on top of this kind of thing.

 

[JoeMerida]

20 hours ago, cadenceblur said:

Battery seems fine, I did a 4:30 rode today and from 100% it’s now at 79%
it also only gets charged once a week before my weekend longer rides , 

Some guy on Another Forum Replaced the Battery and he says his Garmin is 100% Now.

Could be Coincidence that by opening the unit it fixed another problem.

A lot of them are working fine and Some are Not.

Edited October 6, 2025 by JoeMerida