Dexcom G6 - Sensor Error Wait up to 3 hours

Just started on the G6 a few weeks back. Wondering if anyone has the same experience or maybe has feedback on the issue I am having with Sensor errors. Every single time that my blood sugar goes past 9mmol/L (U.S.A. equivalent would be 162 mg/dL) the CGM goes into ‘Sensor Error - Temporary issue. Wait up to 3 hours’. The error clears after an hour or two and then the readings are inaccurate for 1/2 hour or so then back to normal. Next sugar rise above 9mmol/L and Sensor Error again.I am on my 4th sensor and every single one functions the same.

Have talked to Dexcom tech support (who seem to be very friendly) and they ultimately send a new sensor as indicate this is what causes that error. This thing is pretty much unusable as almost every meal I have this issue. Have tried 3 different spots on abdomen and currently on back of arm.

If anyone has any ideas or experiences like this I would love to hear them. I really want this to work for me as the concept is amazing but not when it stops working at the time I really need it.


Is this all happening in the first 24 hours on a new sensor?

When the reading goes above 9mmol/L, is that something you’ve verified with a fingerstick and test strip as well?

The only times I’ve gotten Sensor Error it was in the first half day after starting a new sensor. And is accompanied with wacked out high or low spikes that are in marked disagreement with fingerstick testing. For me it always settles down after the first day (often in the first 12 hours).

Hi Tim12. Thanks for the input! Yes, when able, I have verified with a test strip. The longest I have had a sensor in has been 4 days and it consistently gave me the sensor errors when sugar rises about 9. I am on day 3 of my current sensor and for the last 2 days is as mentioned. This device is so amazing and accurate outside of this issue but unfortunately it not working for a good portion of the waking day makes it unusable…

Welcome to TUD, @supertones!

I’ve had that error only a few times, and like @Tim12 only during the initial-24hr flakiness period, back before I started doing pre-soaking to help calm that down. Haven’t seen it in my last half dozen sensors, maybe more since then. If it’s happening with the kind of regularity you report, that suggests to me it’s not the sensors but something glitchy in the transmitter, since that’s the only constant in the equation.

Others can speak to the specifics of how it works—we have some pretty advanced techies around here—but this error is supposed to indicate the system has judged that it can’t trust its readings and needs to somehow verify itself. Note that the readings you see in the app are not the ones the transmitter sees initially. Somewhere in the circuit there’s data smoothing going on so the graph you get doesn’t jitter about all the time. So there can be things going on that aren’t apparent at the user level and I can imagine that if there’s some bug in the processing you might keep hitting it when the BG data reaches a certain level and it erroneously triggers the “I’m not sure I believe this” conditional, whatever that’s actually based on.

At any rate, I’d see if you can’t get Dexcom to issue you a new transmitter, rather than repeatedly sending you new sensors that don’t make the problem go away.


Thanks for those details! The closest analogy I’ve heard to your experience, is a thread here in the past month, “Ever had a G6 that failed from extended high BG’s?”. The OP of that thread didn’t have that symptom themselves, they were relaying something from facebook, so we never knew details like exactly how “high” a “high bg” is. Link below. Ever had a G6 that failed from extended high bg's? - #10 by Sally7

Hi @DrBB. Thanks for the information and thoughts. I am glad that you talk about the transmitter. I have been thinking it makes sense to try a new one before giving up on the G6. After 4 sensors I would think it is worth trying the only other factor that could be a variable in the equation. (I obviously have no idea on how their product works but when you look at the sensor I don’t see any electronics so assume there is some “smarts” in the transmitter.)

Actually phoned Dexcom yesterday saying that I really would like to try a new transmitter before giving up. The very nice tech support person went through the whole troubleshooting exercise and like all other times calling (think it is 6 times now) came up with the transmitter is fine given the error. Said that they couldn’t send out a new transmitter as their information shows nothing wrong with it. Bottom line: send out a new sensor and if it produces the same results, phone back and maybe they could make a case for sending a new transmitter.

Going to put on a new sensor this evening and should know by tomorrow.

Let you know. Thanks again!!

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Hi @Tim12. I saw that thread but seems different as this thing errors out before extreme highs. Going above 9 is not uncommon (at least for me) after eating. A good reading is 5 thru 6 so 9 isn’t far from that.

Thanks for replying! This forum is simply awesome.

I agree a 9 isn’t that high to me either BUT to some other folks it is high :slight_smile:

For sure. Dang. As I was reading your message my readings hit 8.7 and now I have the same old, Sensor Error - wait up to 3 hours.

People have been reporting a high incidence and variety of errors on G6. This error scenario is unusual, though. I see that error - I saw it yesterday twice, but not with the frequency that you have.

When you have a chance, read the transmitter ID off the back and post it. DO NOT post the entire ID (that makes your device insecure to hackers), just the first 2 numbers are used to identify the model of transmitter. So, for example, 8GXXXX, or 81XXXX, etc. That will tell us if you have an older, more stable model, or a new, more complicated, less stable model. What country are you writing to us from?

Good suggestion. I have used older 80 and currently 81 transmitter and not had any of the problems recently reported.


The first part of the transmitter id is: 81L

Also, I live on Canada.

I have seen ‘Sensor Error - Temporary issue. Wait up to 3 hours’ a good number of times. All of the conditions mentioned have applied over time. However, the most consistent I have noted is a weak Bluetooth signal and my pump (to which the readings are transmitted) is tucked out of sight in the pocket of my jeans or has fallen behind me in bed. To jump start the connection, I lay my pump face down on the transmitter. Inevitably, the signal is restored and the error message disappears. I recall that something was upgraded a little while ago (the transmitters?), and the Bluetooth signal was strengthened. I may have just dreamed it but nevertheless, do not worry - Dexcom have fixed or are fixing the problem. You will realize this when it is time to replace your new transmitter.

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I don’t use a pump. If I get what you are saying, sounds like you feel it may be the transmitter then? Thanks for the info!

Ahhh, ok. The 81 isn’t a very, very new model. It was still kinda new in July. But, there have been many newer models since then. I used an 81 from July to September. I did have failed communications more frequently than now, but nothing like you describe. I’m leaning towards faulty hardware. We may see more issues pop up now that they have made such large changes in their manufacturing. Manufacturing process might not be as reliable now.

I’m surprised that Dexcom tech doesn’t want to take a closer look at the device. I’ll ask if there is someone in town here who might be interested/skilled enough to take a look at it if Dex sends you a replacement. Its kinda interesting.

Thanks for that. As mentioned, Dexcom tech feel that it is not the transmitter since the error shows sensor error. I am now on my 5th sensor and the latest acts the same as the rest. Going to call today and insist on new transmitter as I am pretty much done with trying new sensors.

Thanks for everyone support!


I’m surprised they haven’t offered that yet. Push on them.

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It took 48 minutes on the phone with most of it talking with a supervisor but I finally got them to agree to send me a new transmitter. The supervisors concern is that the same thing might happen with the new transmitter (unfortunately could be true :frowning: ). He started going down the path that maybe it was my phone and version of OS (I have a first version Pixel XL running android 10). I indicated that I am surprised that if this could cause the issue that I would have been told the last 6 times calling that it is a physical sensor issue given the error. Probably grasping at straws but I don’t know.

If anyone has any thoughts or experiences with the type of phone being an issue to cause sensor errors (not the bluetooth connection error, the wait 3 hours error) let me know.

Can you run your original, commercial receiver with it upfront? If the receiver gets data, but the phone doesn’t, you will know its the phone.