670g - "Do Not Calibrate. Updating Sensor" message


My 12 year old daughter started using the 670g about 3 weeks ago. There is so much to learn with this new pump. She had an Animas Ping before with a Dexcom CGM. My head is spinning with trying to learn a whole new system. This is MUCH more complicated than I had expected. Anyway, I wanted to hear from 670g users regarding the message “Do Not Calibrate. Updating Sensor” that pops up now and then. Makes me crazy when it does this. It did this again tonight and I told my daughter to put the pump right next to the transmitter. The good news is it did not take 3 hours for it to update. It asked for a BG after about 45 minutes, so we entered that and it was up and running again. Last week it took 3 hours (from 12am to 3 am) for it to update and told us the sensor needed to be replaced (it was on day 6 of the sensor). The manual does not explain this message very well. I know that this is all a matter of learning as we go. Thanks so much for any input!!!

This happened to me several months ago and the only thing that worked was having Medtronic send me a new transmitter. After I got the new transmitter I never once got the “sensor updating” message.

It seems to me that “sensor updating” is the result of the pump receiving bad data from the sensor. In my case it was a bad transmitter, but it can be due to the sensor being moved or slightly dislodged. I tape it down very tight and secure and always use the two pieces of tape it recommends.

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I’ve had this happen a number of times. For me, it seems to be due to either: end of life of a sensor (day 6 or 7) or the sensor is starting to come loose (adhesive starting to fail due to humidity, water or sweating). I’ve just recently had to replace my 670g due to a technical problem. The replacement has been much better. That being said, its unlikely its the pump- its most likely the items discussed above or a transmitter problem as Sal indicated. I just wish it didn’t tell you the update may take up to 3 hours every 30 minutes. Just tell me when its finished updating or determined the sensor needs to be replaced.

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Thanks so much! The adhesive is actually really secure. I have to use adhesive remover so that it does not hurt when we take it off. The adhesive on the 670g is much better than the DEXCOM adhesive. So, I do not believe it was the sensor coming loose although I may be wrong. We did not have any problems once it was done updating and we entered the BG. But of course, 6 hours later, it needed to be calibrated and started looping for the first time since we got it. This happened at 6:00am and I did not have the patience to try and figure out how to stop the looping so I just took the pump out of AUTO MODE. I made sure the SUSPEND BEFORE LOW was turned on and went back to bed. Although the 670g has been approved for children, I am finding that it is a lot of work in AUTO MODE for children and the numerous highs (350 and above) are not fun. I have had to give my daughter 3 needle injections since we started using the AUTO MODE. Anyway, thanks again for your ideas and input. It REALLY helps to hear from other users.

Thanks Sal! It is so helpful hearing from other users. It is quite a challenge learning how to use the 670g for a child. My daughter and I are so tempted to just use the MANUAL MODE and not bother with the craziness of the AUTO MODE. Will have to just keep finding the time to study the manual, watch the videos, call the trainer, etc… Thanks again!

I was about to give up on it myself after two months of dealing with “sensor updating” and “calibration required” and “calibration not accepted”.

Ultimately I stuck with it and I can tell you that auto mode is the best thing that has ever happened to me since I was diagnosed 14 years ago.

It’s a system that really takes time and patience to learn, but it’s well worth it.

One tip: never calibrate or “accept” a BG reading if it’s too far off from the numbers on the CGM. For example, if the CGM shows 100 and your BG is 200, do not calibrate or accept that number on the sensor. If you do, the sensor will send you through a loop. Wait until your BG and CGM are closer together in number and then calibrate.


Sometimes you just have to wait for update. If it’s a frequent problem call the Help Line and they will help you troubleshoot. Sometimes you have to witch from auto to manual mode for awhile so it gets out of that loop.

I find the 670 very frustrating at times. After inserting a new sensor, I’ll get frequent alerts to enter BG, Calibration not accepted, etc. Medtronic suggested that 1) Wait at least one hour to re-enter BG or 2) turn Auto mode off for at least one hour. Seems to work. Makes no sense to me, but seems to work.

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I get “sensor updating” almost every sensor around day 4 or 5. Alarming super often until it finally fails after 3 hours. I hate it and am so frustrated

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All of the above answers are excellent! Lets see if I can add anything to this.
-AUTO MODE is excellent, but it does take time (months sometimes) for the system to learn your body.
-learn good calibration techniques. You can find many in other posts on this site.
-I find that when I get “sensor updating” it is time to change my sensory location. If this happens often, call Medtronic support and they may want to replace the transmitter.
-If you don’t want to be constantly notified when the sensor wants you to check a BG, you can turn that off. You will then only be notified when it has dropped out of auto mode and into manual mode.
-If you get in a loop, going back to manual mode for a bit does help.
-sometimes I toggle between the two modes when my sugars are high so it will bolus a more (in my opinion) accurate amount. Auto Mode tends to be quite conservative in it’s bolusing for a high and then it tries to recover with basal. If I sugars are over 200, and there is little residual insulin, I might toggle to manual mode, check BG, bolus with bolus wizard and toggle back to auto mode.
-I find that a lower carb diet does wonders for my BG levels. I find that it takes longer for the insulin to adjust my sugars when the carbs are faster absorbing. So even tho I bolus accurately for the carbs, there is a difference in response time. I think this is normal (even with normal pancreas) as our bodies are not able to deal with the refined carbs of today’s diet. Most of my carbs come from fruits and vegetables. If I do treat myself and have…lets say nachos (which I love), then I will see a spike which I have to resist correcting for or I will go low once the insulin has done it’s job.

Now I’m beginning to ramble. But I hope my comments will help. Eventually you will love the 670G.

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Linda, thanks so much for your advice. I went into automode (AM) for three weeks, was very frustrated, went back to manual mode (MM) for five weeks, readjusted my basal rates (I know they are not used in manual mode, but good to have these updated, and it was a great exercise on several fronts) and am now back in AM. I am feeling less frustrated and appreciate the benefits more now. The idea of switching into MM to bolus for a high BG (over 220 or so, if the pump can’t bring it down in AM) is great. That means the pump still registers the bolus, as opposed to taking a shot to bring The BG level down. Thanks again!

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Glad to have helped! I hope you end up loving your pump as much as I do.

I’ve had the “Do not calibrate. Updating Sensor” message a few times. Each time the transmitter was bumped and the adhesive let go, causing the sensor probe to partially pull out. I’ve always had to replace the probe after this happens. After it completes it’s “update” It will give me a calibration not accepted error the next time I try to calibrate it.

Glucose sensors work by using an enzyme (like glucose oxidase) that produces hydrogen peroxide (H2O2) as it reacts with (breaksdown) glucose. The H2O2 diffuses through a special membrane that is permiable to H2O2 onto the working electrode,
The working electrode has a special catalyst coating (platinum?) material that contains binding sites where hydroxide ions (OH-) are bound to the metal atoms at the surface. The H2O2 can adsorb (stick to) these binding sites to form a complex. The complex will then undergo an internal electron transfer, and cause the H2O2 to break down, reducing (extra electron) the binding site, and releasing H20 and O2 as byproducts. As the binding sites return to their original state, they release hydrogen ions (H+) and cause a tiny current to flow in the sensor electrode.

The current is what the sensor measures, and uses to determine the blood glucose concentration.

The “Updating Sensor” messages occur whenever there is a rapid shift in sensor current. This can happen if the sensor becomes dislodged, as the total sensor current depends on the contact between the sensor and the interstitial fluid. Less fluid contact means a proportionally smaller sensor signal.

The “updating sensor” error is the 670G basically saying “Whoa! What happened? I suddenly lost half my sensor signal!”

Like I said, I haven’t had any luck fiddling around with trying to calibrate after an “Update Sensor” message. If you want my advice, just save yourself 3 hours, and change the sensor, because you’ll more than likely be replacing it anyway, when the 670G will not accept calibrations on the “updated” sensor.

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The alerts drive me crazy. I’m alerted 1 hour before a calibration is needed and then once again when it is time to calibrate. The updating is a sure sign your sensor is done. Usually happens at the 4-6 day range for me. If I’m home I just pull the transmitter and charge it if I’m at the 4-6 day range. It beeps and vibrates every 30 minutes and is embarrassing at work and church. Medtronic needs to program settings to allow this less than favorable feature to be turned on or off. And lastly, the range of the transmitter, accuracy, life expectancy, and the lack of compatibility with iphone makes Medtronic’s CGM pale in comparison to dexcom’s G5.
Medtronic is good about replacing failed sensors and the pump portion is solid. Wish Medtronic’s pump was compatible with dexcom’s CGM.

Hi MrEntropy, what are your thoughts about having more sensor metrics that measures more than just glucose. Do you think if there were more biological metrics that the 670g could measure to determine blood glucose, that there would be more accuracy in its delivery or calibration?

I would like to see a system that has a built in step counter, that way the algorithm could adapt to how much physical excercise you are getting. I’ve been hiking several times, and had to turn auto-mode off, because it kept driving my blood sugars low. After about 3 hours (and about 5 packages of peanut-butter crackers), I went back to manual-mode and did a temp basal at 30%.

I wish medtronics would release some of the details about how their “mysterious” automode algorithm worked. I feel like, if I am going to trust my life to this thing (insulin pump), I have a RIGHT to know EXACTLY what it is doing (how the sausage is made).

I don’t know how much effect body temperature has on sensor accuracy. Body temperature should be relatively constant, but if you’re outside in winter, your interstitial fluid just below the skin could be a few degrees cooler. I’m assuming that would effect the reaction rate of the glucose oxidase enzyme and the electro-chemical hydogen peroxide reactions at the probe. You might be able to compensate for that by measuring the probe temperature.

You could sense how much of the probe is inserted by measuring the capacitance between probe and a metal patch on the underside of the transmitter. That would enable the transmitter to detect when a probe has been partially pulled out, instead of just relying on a sharp change in sensor readings to detect when a probe has been disturbed.

I’m generally pretty disappointed with medtronics on the 670g. I’d love to sit in a meeting with some of their engineers and give them an earful. Those bozos can’t even design a belt clip that doesn’t break every few months.

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Hi all,

I just started on the 670g in January and I love it. I had the calibration. Issue that you are talking about on my very first sensor on the last couple of days. I think that the tape had come a bit loose and the sensor was not fully inserted any longer. When I spoke with my CDE she said that there was an issue with some of the earlier versions of this system that caused this to happen. I verified that I have the most recent version. She said that if it continued to cause issues for me I should reach out to Medtronic as there was a fix available (this was before I verified the version).

I have had no problems since and have managed to stay in auto mode close to 95% of the time. Previously, even on the pump and com I was never able to get my A1C below 8.5, I have not had it tested recently but anticipate that when I do so next week it will be well below 8.

I started on the Guardian 3 sensors last year and had the same issues over and over again. They replaced my transmitter and gave me new sensors but still continued to happen.
I put out a message on this site and someone suggested that I put the sensor in my leg.
I have not had a problem since. That was last November.
I know that the leg is not the recommended area and I am an adult with more body surface area than a 12 year old but the leg is very comfortable for me and leaves virtually no mark.
Hope this helps

I was wondering where in your leg you insert the sensor. I’ve had all the above stated trouble for the last 3 sensors and moved from my arm to hip to abdomen with no luck. I’ve considered my leg but my educator has cautioned me against it.

Hi Madison
I’m sure she cautioned you against it because Medtronic did not get it approved by the FDA that way.
But I found it is more comfortable in my upper thigh and I only use 1 piece of their tape and then 1 piece of bandage tape over the transmitter
Give it a try and see how it works for you
Also, try not to over calibrate
People tend to do that out of pure frustration
Let me know if it works for you