HRM-Pro Plus does not stay connected

I am having the same problem.  I've been using the strap for almost a year with no problems until a couple of weeks ago.  Now I am having the same problems as above.  I did all of the above plus I tried removing the device from my phone and my watch and re-adding it.  I've also restarted my phone and my watch.  No change.  So frustrating to not have accurate data and to not be able to figure out what changed all of a sudden. I am wondering if it is a bug with one of the updates on the watch or the connect app.  Thank you in advance!

Have you also tried to reverse the polarity, when changing the battery? Has been around this forum for years, I think it was an official tip from Garmin.

When changing battery, take out the old, flip it over (so that polarity is the opposite of what it should be), insert it again for about 10 - 15 seconds.
Take it out, wait a little, insert new battery.
Try to avoid touching electronics (or even the battery) with your fingers directly, as they will have grease and weak acid from the sweat.

Also you can check, if the HRM is connected to the watch via ANT+. In my experience, it is more reliable inside of the Garmin ecosystem then Bluetooth. (With smartphone and Apps obviously you will need BT, but removing completely from the Apps settings and the devices settings and then re-pairing is a good idea in case of problems).

Good luck.

When I had some minor connection errors with HRM Pro, a battery change (with the polarity thing) solved it.

BJJRunner said:

I've not had to change the battery yet.  My connect app says the battery is still ok.  My problem seems to be more getting the stored data to download after a workout.  It disconnects every 10-20 seconds while trying to download the stored heart rate data when I'm watching connection status on my connect app.

I strongly encourage you to change battery!

Back when I had connection problems with my HRM Pro, app and watch also said "battery ok".
Still, I lost sometimes the connection during activities for a short time and frequently lost connection via bluetooth to the smartphone/app - just like you describe it.

I thought, maybe a bluetooth problem, BUT - just a week or two later, suddenly the app and watch told me "battery low".

Change of the battery solved all connection problems for me. No problems since then.

See my documentation of it here:

https://forums.garmin.com/sports-fitness/running-multisport/f/accessories-sensors/319460/hrm-pro-bluetooth-connection-to-smartphone-unstable-since-few-weeks/1559696#1559696

Thank you!!!  That did it.  I changed the battery last night and it worked like new this morning.  So glad it was an easy fix.

Ok my problem is resolved.

I wanted to wait a little and use my band for a while to be certain that the issue did not come back before posting about it since the solution seemed kind of weird.

So I did what user 3541523 said: