Problems with Medtronic 670G: ("Beginner's frustration" and reps promising that will eventually go away...)


There are around 2000 people worldwide that are using “home-made” closed loop systems that are much more sophisticated than the Medtronic 670G, to control their BG levels. I use a system called AndroidAPS which runs as an app on an Android mobile (cell) phone. The hardware consists of a phone, a Bluetooth controllable insulin pump (model available in many countries but not yet in the US) and a Dexcom G5 CGM.

My experience is probably typical. My levels are always in range overnight and I will wake up every morning close to my target of 5.5 mmol/L (100 mg/dl) without ever having to intervene or look at the pump or CGM overnight. My BGs are in range around 90% of the time (and I don’t eat a low carb or restricted diet. I do still have to bolus, but with the latest algorithm, AndroidAPS will do most of the “heavy lifting”, so for modest snacks I just dial a rough carb count into my phone but don’t bother to bolus. Even for something as carb and fat heavy as a large pizza, I just put in an approximate carb count and bolus for about 50%.



I think that the manufacturers should concentrate on dumb pumps (perhaps eventually 2-hormone) remote controllable via Bluetooth on open systems. That way the smart software engineers can create a series of different control programmes aimed at the various different classes of users.


I bow to your greater experience.

For me the barrier is more about finding a compatible pump. I’m actually using an old pager-style Minimed but my firmware is one version too recent. If it were my kid rather then myself, I would definitely make the effort. But I’m doing well enough as-is that I don’t really feel a strong urge to delve into it.

ETA: “hood” vs “bonnet”–I used to work in a place that sold obsolete British sports car parts (Austin Healys our specialty), so I could go either way. But I’m never going to keep my spare tyre in the boot.


I thought about going for Loop but held off because I wasn’t that keen to use an out-of-warranty vintage Medtronic pump (I still had my old 522). When the 4 year warranty on my Vibe ran out (and Animas went t**s-up) that gave me the chance to push for a replacement of a new DanaRS with a 4-year warranty and fully funded consumables. I could also have gone for a new Roche/Accu Chek pump

SOOIL are supposedly going for FDA approval for the RS (slightly modified for the US market). When that happens it will remove the need to hunt for obsolete Medtronic pumps and I suspect that most US loopers will switch either to AndroidAPS or that Loop will be adapted to include the DanaRS drivers (the pump is already controllable from both Android and iOS devices).


The alarms are louder, which is good for those with minor hearing impairments like me. I often slept through alarms, so did my hubs.


Whew man I’m burnt out on AutoMode. Been in it since January about 85% of the time, overall better control, blah blah blah. But man this junk is overwhelming, in my experience, at times (mostly due to pump errors/bg required/sensors being bad/all this costly stuff). Think I’m gonna just go Manual for a week and see how I feel. I would love to go a week without using a sensor but I’d probably go absolutely insane and check my blood sugar every hour.


I tried the 670 g for about 8 months before going back to using MDI. I found that the sensors were way too frustrating and sensitive, they were constantly misreading my BG’s and in auto mode the delivery of insulin was often suspended due to a “false low” reading by the sensor. This lead to many high blood sugars. Also, the darn thing kept me up all night, beeping and misreading BG’s all night. I found the frustration of the system to not be worth it. Currently, I am back to MDI’s taking a little “pump vacation”. I also went back to using my Dexcom, which is way better.


@Tiff1 hope you’re getting there with it. I still stay a little higher during hormonal times but besides that after 3 months without any outside stress the pump is working. I WILL find a way to manipulate it without going overboard, just don’t know what that will be yet.


I’ve been in auto mode and complaining about it since January 2018 as well. I think it lets me run too high. And if I lower the carb ratio, I crash post meal…but if I leave the carb ratio where it needs to be, I’m running 180 all the time. That’s been super frustrating.

I’ve actually started just exiting auto mode to give corrections.

Overall, I have better control. Far fewer lows and much lower incidence of a high over 240. But running at 150-200 far too much of the time.


No! I came here to vent. In the last months, I have had SIX sensors fails. Today (Monday) I had another one shut down in the middle of dinner with a “Sensor expired”. I inserted it on Saturday. I got 2.5 days out of it.

When I call Medtronic they never acknowledge the sensor failures. They never say “Well that’s not supposed to happen, sir. That sensor should have lasted a full week”. They say “That message appears when the sensor has expired”. They always make it seems like the fault is on my end. One time, when I called about a failed sensor in my arm after just 4 days I was told I was moving my arm too much. Hey, what now!!???

When I see my endo this month, I will be asking her to write me up to go back to the Dexcom G5/G6. The Guardian CGMS system is unreliable. I don’t feel safe using it.

How can we force Medtronic to acknowledge these issues? Can we reach out to the FDA?




I’ve had the same scenario that @JC17 describes. I’ve had the pump alert at 3 AM with a warning I was at 60. I get up and test and the meter says I’m at 115. Then, of course, the meter sends that reading to the 670G which, after "thinking it over for 5 minutes, rejects the reading. Now the algorithm is confused about how the CGMS could be off by 45 points. So it buzzes and asks for another meter reading. This one is at 117. That gets transferred over and the 670G goes into thinking mode and 5 minutes later says “Calibrate now.” And around and around we go.

@Tim35 Security. In fact, in the Safari browser, you have to enable Java apps in an unsafe mode to use Carelink. I get this message whenever I get to the carelink login page.

Note: Browsers such as Edge, Chrome, and regular Firefox version 52 and above (not Extended Support Release) have Java plug-in restrictions that will prevent uploads of your devices.


The infamous calibration loop. I believe the accepted recommendation is to wait it out–when you get that second request just don’t give it the calibration for an hour or so.


New sensors are right around the corner! Per Medtronic Rep and I got a text from Medtronic about it. Amen


Medtronic agent told me to turn off the sensor, wait a minute, then turn it on. That cleared the calibration prompt, but I couldn’t get back into auto-mode for hours.


I registered today for first time because I finally found a place where you guys are addressing exactly what Im going through after being up for past three nights- Im on the 670G and my fingertips are an interesting purple hue. Ive taken my BG every five minutes because I get the message that Im getting kicked out of auto-mode and need to enter calibrate- which Ive just done minutes ago- not 90 minutes- and I calibrate then it asks for BG I enter BG then Calibrate…and so it goes on. I have called customer service so many times and not one single rep told me that its a problem–so I finally get someone who seemed to know what she was talking about and she said give me the serial number of your transmitter, and when I do Im told it is “effected”- and there has been a low supply of new ones so when they come in I will be overnights one, today I got a new sensor , and Im told my new transmitter will be in shortly.
Im really sorry if this is old news to you- Im just thrilled someone else is going through this too- and if this helps I would like to help others who feel like ripping this crap off and go back to the pens.


I’ve been thru all that, the ‘loop’ and had my transmitter replaced. It’s not perfect but I still give the system two thumbs up. Per a Medtronic Diabetes rep and per Medtronic texting me, a new sensor is in the works.


I tried the 630G for almost 3 months. It drove me crazy. I returned it and went back to my 554. It’s held together by tape but it still works. I tried using the Medtronic sensors with the 630 and they drove me nuts too, although having CGM was an eye opener. I decided to try the Libre with the Miaomiao bluetooth link connected to my smartphone and smartwatch using the xDrip+ app. It’s been brilliant. I can’t recommend it enough. The Miaomiao is rechargeable (quickly), so no batteries and I’m expecting it to last for a while. It’s CGM on a budget. Plus, I’ve been pretty good about calibrating every day and the sensor is really close to my BG readings. The app warns you when you’re going high or low, which was what I wanted and it doesn’t take over your life. For the first time in 24 years I actually feel like I’m in control.


I too was a Animas /Dexcom user with the same issue. I made the mistake of selecting the 670G, this thing was the worst decision I ever made. the Sensors only last 4-5 days, their tech support claims " they can last up to 7 days" the magic word being They can… Medtronic customer service has been very unresponsive, They say they wil have someone call you, however that never happens. Medtronic has a 30 day return policy, but be forewarned, in my case I received my pump on Dec. 12, 2017 with the transmitter for the CGM. did not receive it until an 28,2018 some 6 weeks later. I never received any training on this system until Aug. 2018. It was 9 months after I received the pump, so that was 9 months of trying to set up the Pump and CGM, numerous calls to Medtronic tech support with limited help, They are really set up to trouble shoot problems, not instruct users on the system. They told me someone would call me to schedule training, ( that finely happened 9 months after I received the pump.

Here’s what I have learned so far.
The sensors should last 7 days, reality is maybe 5 days.

The CGM can be off by as much as 20% on readings. ( they are ok with the 20%, acted like this is normal. my experience is they are off by as much as 50-60%. CGM will show 148, actual finger test shows above 200. this is the normal for me.
The reservoir will show empty when there is still about 10-15 units left, Very wasteful .
I have started working with my doctor to go to the T-Slim/ Dexcom G6 system. I have been very vocal on twitter and finely Medtronic called to discuss, I let you know the results. I am fighting to return the system and get a full refund. My insurance will not cover a new pump, So I will have to pay for the T-Slim/Dexcom out of my own pocket. But what can you do, its my life at stake.


There is a new transmitter available with updated software to correct this issue, Call tech support, but be advised you will have to watch your BG, this new CGM is off greater than 50-60% from your true BG. I have had the new one for two weeks. been nothing but hell, will show bg in the 140’s however you will be mid 200 range.