Restart Dexcom6 not accepting calibration?

Hi friends!

My G6 has been temperamental lately on restarts.

This go-round, it is almost 100 points higher than my finger sticks and won’t recalibrate to the newer/lower level.

G6 won’t even accept a slightly lower BG level and reverts to a super high.

I’ve tested multiple times on different fingers and feel they’re much more correct.

Any thoughts?


So one thing is that the calibration cycle seems to occur in two stages: first it just splits the difference between whatever its own reading was and the new number you’ve given it, then it does a full update at the next 5-minute interval and settles the calibration value you provided. I think the first response is just to reassure you that it is doing something but for whatever reason it doesn’t want to reset to the manually-entered number until it’s done its next sampling.

But what you’re describing sounds more like something I experienced a few sensors back. I think it was a restarted one, but at any rate I recall that it was near the end of a session when it started giving me sudden high numbers out of the blue, kinda like what you see with a compression low only the opposite. Calibrating would settle it but then it would happen again. After a couple of these I decided it was just an exhausted sensor and swapped it out for a new one. Took me a while to decide, since I usually get another full 10 days when I choose to do that (usually just to build up my emergency reserve stash). But they do crap out eventually.


I’ve been having an issue recently too. The last two new sensors in a row have pulled it. It wants to revert almost immediately, even a double calibration which it used to take as gold. Both sensors started out high, but later ended up dropping me really low when I wasn’t. So I calibrated and within minutes it dropped back to saying I was really low. Repeat several times. I kept working with it and then it acted fine for a day, but started it again. I called it in. I put on a new sensor and repeat the same problem for over an hour of repeated calibrations. It wanted to keep reading me at 40’s and 50’s. Called it in too.

I asked them if they had changed programming and all they said is when this happens it’s a bad sensor. So they either have and they won’t admit it, or they are having a rash of bad sensors, which is completely possible. I was just told if the sensor won’t take a calibration 3 times that it’s a bad sensor. They did ask for the lot numbers which I can’t remember if they have done before as I rarely have to call in bad sensors.

In this case since they were from different boxes and lots I wondered if it was the transmitter since I had put in a new transmitter with that first bad sensor. I asked and they said no a transmitter wouldn’t do that. However after lacking sleep a few days and being suspicious, and since I had a back up transmitter I plopped it in and paired it with the “bad” sensor I had on. It was in the morning so I had all day to replace the sensor if needed. And guess what? The, sensor is acting completely normal. Started high, I calibrated it, I’ve refined it better a few times like normal. It started off 25 points lower than I was at this morning, but that’s normal for a new sensor and I usually end up refining it a few more times the first full day. But it’s acting normal.

So I am left wondering if it’s the transmitter or if it’s the sensor and I cleared it by restarting. They’ve been known to try to change programming before to try to stop us from doing things. But it could be just restarting the sensor solved the problem?

Has anyone taken off a transmitter and then able to use it again if it has time left? I would like to experiment with a new sensor and the “possible” bad transmitter to see what happens. But I only want to do that if I won’t ruin my now current transmitter by taking it out and having to re-pair the transmitter again.


It doesn’t seem to be the transmitter. The restart must have it given it a couple days of normal life. Okay, put on a third sensor. It starts out at under 40 when I am at 139. So of course I calibrate with only a partial calibration because that is too big of a gap. It does fine but 5 hours later it’s still over 50 points off, so I calibrate it again. Still off but closer. Right before bedtime it shoots up 80 points WT? I check with two different meters to make sure of what I am at and sure enough the sensor is very wrong. I calibrate it and it reverts back, I try again it reverts back, third time, still no go. I shut off my phone and receiver for the night, I want sleep.

I started thinking what is wrong with my body, because 3 different lots and 3 bad sensors in a row? But I wear a Libre for when I swim ( I haven’t been swimming since this started, It is still working because it’s 14 days). My Libre is being normal, 25 points under what I am at. Common and has been that off since I first put it on. So it’s not me.

So now I deleted the ap on my phone, I am going to start a new sensor with just the receiver and see if that makes a difference. It’s a very frustrating experience.


Thanks, @Marie20 — what a wild ride. I got so frustrated I restarted with a new sensor and the “new” is just acting up.

I’m shutting it off during the day as it’s wildly swinging to lows while I’m at work (desk job/calibrating). I’m definitely leary of trying a new transmitter out of cycle. They just jumped up in price for me after being $30 (now $78).

@DrBB — I hear you on just accepting and putting a new one in. I was at the point I was using more finger sticks to calibrate than it was worth to just put a new sensor in.

Glad to hear these things happen and it’s not just me/user error.

Thank you, both!

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I’ve had this issue with in the first run of a sensor. I usually don’t restart them. But when I’m getting a low reading in the 50s but I’m really 85 it allows me to calibrate to 85 but a min later it’s back to 50. I retest my blood and at 83, so I cal again and back to 51. The only way out is to eat something and calibrate when the sensor reads higher


I deleted the phone ap and started a 4th new sensor with my receiver and a new transmitter. It worked as normal, took calibrations as normal. I used it for 9 days, but I really wanted my phone ap back because it is nicer. So I called the 3rd sensor in and that I replaced the transmitter, deleted the ap and that it’s been working fine. So Dexcom thinks it was the transmitter and that I shouldn’t have any issues with redownloading the ap and using it. So I did and it’s working fine and taking calibrations.

They gave me no issues with replacing the 3rd sensor and the transmitter, that they could see my history. The rep did say I wasn’t the only one that had had an issue.
So I am back to normal it looks like. A very frustrating experience.


One of the things that will be eliminated from the equation with the G7

Restarts are eliminated, right?

@Mika – Yeah, I haven’t heard of anyone restarting a G7.

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I have never ever been able to restart a G6. No matter what method that
I’ve tried.

I continue to do restarts with G6. There are several posts with videos. In early days of G4, G5, it was much easier.

Have you seen this youtube for G6 ?
Instead of test strip, I use edge of my costco membership card, which is stiffer than test strips I use, but thin enough to pry out transmitter while still on skin.
The two clips on the long sides that holds transmitter need to be released by sliding thin card or other thin, stiff object.