Dexcom 7+ Failed sensor, now gray bars on the receiver

Hello, Dexcom 7+ users. Inserted a sensor ... got a ??? then "sensor failed" message about 20 minutes into the start-up 2 hours.

Ended session, inserted new sensor, started new session and ended up with 2 gray vertical bars on the receiver screen that won't go away even as the rest of the gray box is turning white as it gets closer to 2 hours.

Waiting to see if this sensor is able to be read or not. Anyone else have something similar happen--any tips? Thanks!

Call Dexcom. And/or try a reboot. There's a tiny inset button on the back. It takes a toothpick or something similar to depress the button. Push and hold for about three seconds.

It sounds like the display may be faulty. Can you snap a picture and post it? I'm certain we (Dexcom users) could tell someting.

Thanks for the tip about the reboot button. I didn't use it, but good to know it's there.

After 2 hrs, I entered 2 fingersticks and now the first few readings are appearing. Vertical gray bars still visible on edge of trend screen, but maybe they'll go away as time elapses. I'll definitely call Dexcom on Monday--I want a replacement sensor!

Hi, Danny! I'm looking forward to all the cgm data. But still loyal to my old skool diabetes management ;-)

The grey bars are just the time you "didn't" have a sensor working... it's no biggie. You'll see the same thing at the end of a session, if you delay more than a minute or two before starting another (restarting the sensor, that is.. you'd obviously get some grey area if you changed out the whole sensor because of the time it takes).

Thanks, Sarah! I was confused because there were stripes of gray and white--but that must have been the faulty new sensor. Things seem to be back on course now.

I've had it on for a week--and I think my A1C is down to about 5.2--NOT! This new technology reminds me that staying on the straight and narrow is important--in trying to quickly lower highs or raise lows, it's apparent the technology just can't keep up. I'm curious if this device is truly helpful for people who have abrupt low lows--it seems to be living up to its so-so accuracy stats (did you see the number of readings in the false "normal" area on the Clarke Error Grid in the user's guide--readings that were actually lows?)

"abrupt low lows"


I assume that you refer to double down arrows. I had a lot of these in the beginning. Nowadays I rarely see double down arrows. I did not change my diet. I just got better at timing. Just seeing what is going on will improve your control. I don't think too much. I play the dex like a video game. I bet anybody will get better at any video game if she/he plays it 24/7.

I like your video game analogy!

I got the Dex to tighten control; hypoglycemia unawareness is not an issue for me at this time, although I'm less able to sense symptoms than I used to be. I'm eager to try some bolus timing experiments. After one week, I'm starting to see that I need to time bolus and first bite based much more on starting bg and planned meal than set 15-20 minutes. Make sense, of course, but until the trend lines are staring you in the face, can be hard to change those old habits!

It would be much more fun if the controls were on a joystick!

It took me 3 months to become proficient. The biggest challenge was the delay. When I was low I would eat and watch the dex. When I was still low 10 minutes later I would eat more. Eventually I would see double up arrows and go too high. Then I would over-bolus and start another round of chasing my BG. Now I take the correct amount of fast-acting carbs when I am low and totally ignore the dex for the next half hour. Same when I am too high. I correct and ignore the dex for the next hour. I knew about the delay. I am still surprised how long it took me to not be fooled by it.

I have abrupt and extreme lows. The Dexcom (and years ago, the Guardian) is helpful but not fully effective.

For one thing, it doesn't wake me up in the night. For another, it has some delay sometimes. For a third, my meter is not perfectly accurate- last time I had a blood draw for a CBC, my meter had just read 86, Dexcom was saying ??? but apparently my blood sugar was actually 62. And as I just alluded to, there's the problem of the ???s. On the Guardian at least I could set an alarm to go off at night if I was not getting readings, but not on the Dexcom.

Then there's the issue that the CGMSes only help with detecting lows- it doesn't make treating them that much more successful. I go low partly because I don't digest my food all that well. So the Dexcom can be telling me that I'm headed down at 100, and I can start eating, but 50 minutes and 50 carbs later, it may be saying LOW (below 40) anyways.