Enlite Sensor issues

I got the new Enlite sensor about a month ago and had the older sensor a few years ago but I hated it. I’ve been having problems getting the sensor to work correctly. Two of the sensors I’ve had to take off after less than a day. The first time it kept saying weak signal and then lost sensor. The second time I had a weak signal, got it working, and then had calibration issues. I turned it off in the middle of the night because it said I was low when I wasn’t and I turned it back on in the morning. I turned it on and it told me to test, then it said calibration error and change sensor. I’ve been using my abdomen and side for sites. So far, my side has worked the best, even when playing soccer and diving on it (I’m a goalkeeper). Anyone have any suggestions? What sites have worked best for you?


I had a lot of problems when I first got my invite about a year and a half ago. I was very disappointed with it in somewhere to your experience I was quite upset with the results I was getting. I was constantly on the phone with Medtronic and they were sending me new sensors all the time.

I have used it up on my leg and it worked fine I have used it on my stomach primarily and it generally is okay. I think I’ve learned that it depends on how you tape it down so that it stays in place. I’m assuming they sent you a new transmitter with the in Enlite? The transmitters are good for maybe a year or two years although mine is lasted for about four years. If you haven’t had a trainer come overto your home or go to a center and have a Medtronic trainer look at what you’re doing in the exercises you’re doing it might be a good idea.

Best of luck, Scott

The first thing I would suggest trying is viewing the insertion demo vids on the YouTube channel for Medtronic Diabetes ANZ (Australasia). There are recently posted newer demo vids for the Enlite there which are, in my opinion, vastly better than the “meh” vids I’ve seen from the US branch of Medtronic. What I feel makes them better is that they point out a number of mistakes one can make while inserting or taping which can lead to problems later.

Yes, they are still as tedious as watching paint dry. But I think they are still worth looking at at least once to see if they cover anything which you might not have considered before.

There are seven vids, each about 2 or 3 minutes long. The general title of the vids is “Get Right with Enlite”. For some reason Medtronic Diabetes ANZ has not created a playlist containing all seven vids so I did it myself. Here is a link to a playlist containing the seven vids on my personal YouTube account: Get Right with Enlite playlist.

Because I can’t promise that I’ll keep the playlist available forever, I’ve also listed below the titles, running times & direct links to the seven individual vids. Note: you can always skip the last 20 seconds or so of each vid since it’s just CYA “This is not medical advice. Ask your doctor before continuing to breath.” boilerplate.

Get Right with Enlite - Chapter 1 Introduction (1:57)

Get Right with Enlite - Chapter 2 Site Selection (2:16)

Get Right with Enlite - Chapter 3 Loading the Serter (2:12)

Get Right with Enlite - Chapter 4 Inserting the Sensor (3:49)

Get Right with Enlite - Chapter 5 Taping (2:58)

Get Right with Enlite - Chapter 6 Transmitter Connection (1:53)

Get Right with Enlite - Chapter 7 Additional Taping Methods (2:45)

T1 LADA since ~1978; first pump: Minimed 507 ~1996
current: Paradigm 723 (Apr 2013) + CGM (Dec 2014)

I tried the enlight system a year ago for a couple of months and I never got it to work correctly. It was never accurate and had constant failures, especially during the night. Twice it shut my pump off due to the low suspend feature, while I was asleep and my blood sugar was nowhere near low. It made managing diabetes so much more stressful than it already is. Medtronic treated me like I was crazy and must be doing something wrong, because nobody else had the problems I was having. After writing a couple of posts like yours, I realized from the responses that in fact these problems happen to ALOT of people. Several people suggested to my that I try Dexcom instead. Finally I convinced Medtronic to allow me to return it for a refund and I started using Dexcom. It works perfectly all the time. It is nearly spot on accurate all of the time and I can usually get 2+ weeks out of one sensor. I have been using it for nearly 8 months and have had no failures. I cannot imagine not having it with me all of the time. Hope that helps. Good luck!

In a previous reply I posted, I suggested viewing the insertion instructional vids made by Medtronic Diabetes ANZ (Australasia). Unfortunately that post has disappeared into the bowels of this discussion board until someone “in charge” can kick it along.

I included links to the suggested vids in my earlier (missing) post. Hopefully it will turn up eventually. Meanwhile, if you want to look at them try searching for “Get Right with Enlite” on YouTube.com.

Some other speculations about Enlite weirdness.

“Weak signal” can happen for a lot of different reasons. Possibly choosing a different orientation for the sensor/transmitter on you body might help? (horizontal versus vertical versus 37.132 degree angle versus whatever?)

Probably the most common reason for “weak signal” in my case is that my body comes between the transmitter and the pump. Usually this happens when the pump is on my waist & it slips around behind my hip.

Where do you currently insert your sensor and wear your pump?

I currently think that, aside from the location used, the key thing needed to ensure the Enlite works correctly is to ensure the sensor base & sensor probe stay put after insertion. I think accomplishing this is key to both get accurate readings & the full six day life out of the Enlite.

One possible problem can stem from the Enlite sensor tape being pressure sensitive. It needs to be pressed in place to adhere properly. That is why the Medtronic instructions are to hold the serter gently in place against your body for 5 to 10 seconds after inserting. This is to allow the pressure sensitive tape time to adhere properly.

After the tape sets, remember to press the big honkin’ green button again BEFORE you remove the serter. I realize it is confusing to have to press the button twice to “properly” insert the Enlite, but, well, it is what it is.

When you unfold and apply the other “accordion folded” sensor base tape flap, you also need to press it gently against your body to ensure it adheres properly.

Review how you apply the Enlite overtap to ensure it is holding the sensor base snugly against your skin and preventing the sensor base (& sensor probe) from shifting.

Don’t pull the tape tab which folds over the transmitter (to keep it from flopping around) too tight. If this happens it can result in lifting the transmitter slightly and a “rocking” or “seesawing” of the transmitter/sensor assemblage can occur. This can then pull the sensor probe up out of its insertion site with a “pistoning” motion.

If the sensor probe moves it will can cause incorrect readings & calibrations. If the sensor probe moves too much it will cause the transmitter to reset which can be one reason you can get the “replace sensor” alert message.

T1 LADA since ~1978; first pump Minimed 507 ~1996
currently: Minimed Paradigm 723 (Apr 2013) + CGM (Dec 2014)

Thanks for all the suggestions! I met with a CDE whose daughter has type 1 with a Medtronic pump and Enlite sensor, so she had some good tips for inserting it but have not met with someone from Medtronic. I went on their website today as well and did some troubleshooting and am going to call and hopefully get some replacement sensors. I normally wear my pump on my hip, but I did notice if I moved it more to the front when my sensor was on my other side that it did seem to work a little better and fix the weak signal (somewhat).


I normally wear my pump on my hip, but I did notice if I moved it more to the front when my sensor was on my other side that it did seem to work a little better and fix the weak signal (somewhat).

I personally find it very surprising how opaque our bodies apparently are to Medtronic’s CGM radio frequencies. One of the most common reasons I will get a “weak signal” alarm is that my pump has slipped into a position which puts my body directly between the pump and the sensor.

Having the pump slide around behind the hip opposite the side of my body the sensor is inserted on is one case. I’ll also get “weak signal” or “lost sensor” if the pump is laying on the bed on the side away from the transmitter when I’m in bed. You’ve just got to treat the pump and the sensor as a “bonded pair”. If they become separated by too much distance their relationship dies. :wink:

I’ve heard some folks talk about inserting the CGM sensor behind them, either on their upper butt or lower back. First, I assume they have help when they do this because I have no idea how I’d put the overtape on. But I also wonder where they carry the pump so that it can talk to the transmitter when it’s behind them?

In my opinion, the weak signal strength of the transmitter is one of two basic design flaws of Medtronic CGM. Unfortunately, all indications are that Medtronic is not going to do anything over the next few years to address these fundamental flaws.

I had hoped that the signal strength of their CGM transmitter would be improved when the current MiniLink transmitter is replaced by the upcoming Guardian 2 transmitter. This new CGM transmitter is currently being introduced outside the US for use with the new Minimed 640G pump.

Turns out, apparently not so much.

The FAQ for the new system on the UK site leads me to speculate that the signal strength for the Guardian 2 transmitter will be the same as the MiniLink. What Medtronic has done to try to address the “weak signal” problem is to increase the number of CGM readings which can be buffered in the transmitter. The MiniLink can hold up to 8 readings (40 minutes). The Guardian 2 appears to be able to buffer up to 120 readings or 10 hours.

So if the pump and sensor are unable to talk to each, then with the new system so long as they reconnect within 10 hours no data should be lost. Of course, that doesn’t really address the issue of how the pump will be able to stop basal insulin when you go hypo during the night but your body is blocking the pump from talking with the transmitter. I wonder if the FDA is going to raise that question during the US approval process. (Does the FDA web site have a place for public feedback?)

Anyway, while the Guardian 2 is an improvement, it’s not the one I was hoping for.

The second fundamental Medtronic CGM design flaw in my opinion is a consequence of how they attach the transmitter in line with the sensor. Dexcom places the transmitter over the top of the sensor which I think works better for them.

The potential trouble with Medtronic’s approach is that it positions the sensor probe at the end of a “lever”. It allows the sensor transmitter pair to potentially “seesaw” and move the sensor probe in/out of the insertion site. If this happens it can result in fluctuations in the reported ISIG which have nothing to do with changes in the interstitial glucose level. In other words, the sensor’s accuracy gets shot to hell.

I am not sure how Medtronic can “fix” this long term other than by redesigning the layout of the sensors. And obviously that ain’t gonna be happening any time soon. In the mean time they focus on the improving the adhesives used to hold the sensor in place because … well, what else can they do to fix it? The mechanical advantage is working against keeping the sensor probe fixed in place.

Frustrating. Of course, people just see wildly inaccurate readings or calibration errors and think Medtronic’s entire CGM system is crap. I tend to doubt this. I think it’s more that the design doesn’t lend itself naturally to being used properly by actual, active, living human beings with lives that go beyond tweaking with their CGM system.

T1 LADA since ~1978; first pump: Minimed 507 ~1996
current: Paradigm 723 (Apr 2013) + CGM (Dec 2014)

I will definitely check out those videos. Thanks again for everyone’s input. I’m going to put my Sensor in again Friday so I’ll let everyone know how it goes.

I’m happy to report that my sensor has worked perfectly all day! I also called Medtronic and was able to get a couple replacement sensors sent. Thanks again to everyone for your suggestions.