Garmin Speed Sensor 2 does not provide pace nor average pace for Garmin ForeRunner 735XT

Is it fair to assume you're talking about using this on a bicycle for speed and average speed? Have you checked the battery?

Any particular reason why you're connecting it via Bluetooth? It'll connect better to your watch using ANT+. Use the Bluetooth for indoor use.

I'm talking about using this on a bicycle for pace (min/km) and average pace (min/km), so that I can do minutes per kilometer pacing for an elite runner, that is following my bike. He is running speed endurance training, so he needs to stay on correct, fairly narrow pace zone. But you might be right that this device might only deliver speed (km/hour) and average speed (km/hour), since I assume the device is mainly designed for cycling, not running. Good idea, thanks! I have to check if that is so. Then I just do the required km/h->min/km calculation in my head.

And again, you are right, it used ant+ to connect, not bluetooth. Connection and pairing were succesful, and I was able to set the wheel size. But then I didn't get the min/km reading. I didn't even check km/hour. Now I will.

This has nothing to do with the sensor. The sensor provides neither speed nor pace. It provides wheel revolutions, which are then recalculated by the watch into speed/pace based on currently set wheel size. I don't have the FR735XT anymore, so I cannot guide you directly, but on some other garmin watches you can configure whether you want to see speed or pace for cycling. Look in the watch settings. Please note, that the source of speed/pace data doesn't matter. This setting applies for both GPS-based speed/pace and sensor-based speed/pace.

Thanks tmk2. I now changed ForeRunner 735XT's cycling profile to use min/km instead km/h, and will test tomorrow via cycling profile whether it would somehow work. If it doesn't, then I will test with athlete's ForeRunner 745.

Have you checked the battery?

I will check that tomorrow as well. I happened to have new CR2032 for that.

My son is a Track & Cross Country coach and also uses his bike to pace runners.  He hit the same problem as you.  The solution was to download a CIQ data field that displays pace in a bike profile.  So you are able to use the accurate speed sensor and have the data field automatically calculate pace instead of speed.  I'm not sure which CIQ dafa field my son uses, but here is a possible choice:

https://apps.garmin.com/en-US/apps/5bcd8fd2-b151-421f-bb7b-d1bb6b1e65f1

Thanks Dan. I downloaded CIQ data field to my Garmin ForeRunner, changed a new battery based on advice from Philip, and will do a test run as soon as heavy rain stops.

It works!  Thanks Dan, Philip and tmk2. I changed the battery and downloaded CIQ data field. I used cycling profile, and can now see average min/km from CIQ data field, which is exactly what I need. I can now also see km/h from normal speed field and average km/h from normal speed average field. For top runners, accurate pacing during key exercises is critical, and during bad gps weather or close to buildings or trees, or when track running, the GPS accuracy is just not there.