Heart Rate Monitor pass through not working after firmware update [v4.0] [February 2023]

After upgrading to v4.0 the ANT+ heartrate passthrough is not working anymore. I’ve disconnected & paired my heartrate strap a few times but this did not help. It used to work fine before the upgrade and using the a separate ANT+ dongle it works fine as well. Zwift sees the Bluetooth passthrough and can connect but the heartrate is always 0 (— on screen)

I noticed the same issue with the heart rate pass-through yesterday. I am using the Bluetooth Bridge through the companion app since v4.0 isn’t working with my PC (troubleshooting with support) and I had to separately connect to the heart rate monitor instead of passing it through the hub since it was showing up as 0 through the hub.

@Iljitsj_Bos and @Matt_Parrish

Thanks for your reports. You haven’t said if you’ve tried re-pairing your HRM to the Hub trainer after updating the firmware. Have you tried that? Here are the instructions. Same result?

I’m still on the bad v4.0 update as there is no way to downgrade back to 3.9 and no 4.1 fix yet.

I’ve re-paired a few times before without success but when I re-paired just now it seems to work again. Hopefully it keeps working from now on.

1 Like

Want to understand more clearly what you’re saying. Are you not able to repeat the process to pair the HRM to the Hub trainer with firmware v4.0?

We’d like to see what you’re seeing. Can you grab a screenshot of the Companion app when you get to the the Zwift Hardware > Zwift Hub > Pair Device screen?


Thanks for reporting back. Please let us know if the HRM pass-through stays stable, or not.

@shooj I just tried this again and here’s what I found. I opened the Zwift app on my PC and it paired to the companion app like before with a 0 reading for the HRM. I was able to successfully unpair and re-pair the HRM to the companion app via Ant+ and then Zwift started showing my heart rate correctly. I’ll keep an eye on it to see if that changes at all.

Thanks for investigating. Those two methods of paring the HRM to either the PC or to the Companion app are different than the card trick that the Hub trainer can do.

The card trick is to bond the HRM to the Hub trainer, and the Hub will relay your heart rate to the Zwift game app. It sounds like we’re talking about two different things here.

I’ve split this discussion to its own dedicated thread. While it’s good that you were able to re-bond the HRM signal to your Hub trainer, we’re investigating why it took several tries.

If other people are having issues with the Hub trainer’s heart rate monitor pass-through feature after updating to firmware v4.0, please weigh in here. Thank you.