Speed Sensor keeps showing zero speed intermittently

If you have a GSC 10 check the magnet alignment. I should be centered on the line on the speed arm and the gap should be 2 to 5mm.

I paired my speed and cadence sensor with my Garmin 800 with the latest update.

The speed keeps showing 0km/h intermittently while I am cycling on the move. It irritates me during rides especially when I need to maintain my speed.
Pls help. Any idea why?

The magnet alignment is incorrect/the sensor arm alignment is incorrect/the sensor is failing/a new battery is required.

The magnet alignment is incorrect/the sensor arm alignment is incorrect/the sensor is failing/a new battery is required.

I am using the ANT+ speed sensor attached to my front wheel hub. The red light is not blinking; it ain't low batt.

I have had that problem with one of my speed sensors when it was new. Others have seen it too but it seems to go away. I think it is a battery contact issue. Try rotating the cover between the locked and unlocked position a few times to get the contact better seated. You could also try taking the battery out and reseating it but I would be interested to see if rotating the cover is the solution.

I have had that problem with one of my speed sensors when it was new. Others have seen it too but it seems to go away. I think it is a battery contact issue. Try rotating the cover between the locked and unlocked position a few times to get the contact better seated. You could also try taking the battery out and reseating it but I would be interested to see if rotating the cover is the solution.

Alright, I will replace the original battery (which came with the new speed sensor) and see if this problem goes away.

I think the problem is with the contacts and not the battery. So you don't need to replace it. Just take it out and put it back in. Also be sure to rotate the cap between the locked and unlocked position a few times.