Dexcom Sensor Failures

So we just received a new batch of sensors last week and this evening I had to change my daughters. I received a sensor failure. My wife says she has been reading up on them and they can be common with a batch. I decided to replace it and put another one on my 7 year old. 7 year olds don’t like to be poked. An hour later I received another sensor failure so I replaced it again. I am now on my 5th sensor tonight. It is 130am and am done with replacing these sensors. I took a sensor from another box hoping to get away from a bad batch. Has this happened to anyone? Am I doing the right thing bu replacing the sensor? Is there a trick to this. I have tried stopping and starting the sensor but I still get a failure. I will be contacting dexcom in the morning. This is such a pain in the ■■■ and I do not want to send my daughter to school and go back to finger prick method. I look forward to hearing from you fine people. Cheers.

What type of failure?

It just says sensor failure. Not sure what it is

Call Dexcom Technical Support.
They are always open.
Sensor failures are not common.
Something is absolutely wrong.

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@Josh101, @Tim35 is right. In 18 months we have only had two official “sensor failures,” although, of course, many more sensors failed (without getting a “sensor failure”). Getting several sensors failing in series is totally abnormal. Dexcom support will help you figure it out, and will also replace your bad sensors.

Make sure to tell them how many went wrong, or you’ll run short.

Will do. I replaced the transmitter and entered the serial number. Still had the error. My wife read that a lady had 8 sensors fail at one time. I’ll be calling in the am. So far so good with the last sensor I put on my daughter. Just waiting to calibrate so I can get some zzzzzzz. Thanks guys.

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Josh, FYI they are open 24x7: 888-738-3646. Good luck! Getting zzzs is critically important for us parents, this BG monitoring is a long-term task :slight_smile:

Always possible, but extremely unlikely for anyone.

Be careful about transmitters: when started, they can’t be stopped, and they only work for 90 days. They are also quite expensive—I think $300 a pop?

could be time for a new transmitter. Dexcom tech support will know. This isn’t normal. You had a new transmitter just laying around? Or they shipped u a new one?

Are you sure its not your insertion technique? Maybe run into the Docs office and have the nurse try.

Another possibility might be if its cold where you are and the sensor is under a bunch of blankets, separated from the transmitter.

Definitely not our insertion technique. The last sensor I took from the different box work. All is fine now. Thanks for everyone’s feedback.


I just called Dexcom this morning about a different issue. But they had me check my Sensor while trying to figure out what was wrong with my Transmitter. The technical guy said that sometimes the thin metal wire doesn’t insert into your body properly or if you pull off the bad sensor you won’t see a wire. Mine had the wire attached and they will replace the Transmitter. They are also replacing the sensor.

I am definitely going to try to buy an extra Transmitter since now I am without a working device until Wednesday. I always have extra sensors on hand though.

Make sure you call to request replacements for the bad sensors. Hope you have some peace of mind now that it’s working. It’s good you had the extra sensors on hand.

How much is a new xmitter (I’m on Medicare, so an EXTRA xmitter would be something I’d have to pay OOP)?

How long do xmitters last sitting in the box, unused before one can’t get the normal 122 days of usage out of it?

I’ve used Dexcom cgms since the G3. Late in the G5 lifecycle, sensors have failed repeatedly. Since starting the G6 in March 2020, there have been only three sensors which have lasted the full 10 days. (It is now mid-August.) Dexcom technical support used to be very good. Now they are worse than the worst cable tv companies. Sure, after waiting on hold for two hours (no exaggeration), they replace sensor after sensor, but they refuse to even allow me to speak to someone with knowledge or authority within the company. I’ve asked many times to speak to someone about their repeated product failures, but they either refuse or lie, promising to have a “supervisor” call, but they never do. Look into the Medtronic cgm. My life is more important to me than to continue to put up with their incompetence/corrupt corporate motives.

Sorry to hear that. Many here, including me often get 10-20 days per sensor.

What location(s) do you wear it?

Have you tried delaying the start sensor so that it has more warmup ime? There is often “trauma at insert”, and waiting often helps to let skin settle. Keeping hydrated also may help.


I am reaching out to see if anyone has a suggestion for my Sensor Failure Problems.

We are evacuated from Hurricane Laura and cannot go home. We have no idea when that will happen.

Over the past three days I have had three sensor failures. These sensors have nothing in common, not lot numbers, nor any other identifying factors. Tandem insists that the problem is the sensors and not my pump.

I did read one post suggesting allowing it to settle a bit before starting it. I will try that, but another 24 hours will pass without a sensor. My stress level is higher than usual because of our situation, and I need my pump to work.

I anyone else experiencing Sensor Failure to this degree. Nothing has changed in the way I insert it, where I insert it, nor anything else. Any information will be greatly appreciated.

Thank you as usual

Is tandem replacing the sensors? Hope so.

Do they start ok after 2 hours, then fail, or fail before 2 hours.
If you get some readings, have you bg checked to see how accurate they are?

I’m sure with hurricane, etc, your stress and adrenaline may be through the roof, hope you are safe. But that could impact sensor.

Does it give just error, or does it give some readings way off or very jittery ?

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Hi there. Yes the sensors are being replaced one at a time. That means with each failed sensor I have to wait 24 hours for one to be overnighted. The sensors in question never reached warm up status. In fact; they give a Sensor Failed message within 30 minutes of insertion.

I examined two of them and found the following: 1) The Sensor was just lying flat on the tape and 2) The Sensor was bent so I understand why that one did not work. I have been using these for a year or longer and had no problem. I am using the same technique for insertion as always. Everything with the insertion is pretty straight forward with little room for error. I even went over steps with Tandem to verify that I am inserting them correctly.

Before inserting the last failed Sensor (yesterday); I called Tandem and had them make sure all my pump settings were correct. When it failed I called back and told them I thought the problem had to be the pump. They assured me it is the Sensor and not the Pump. They acknowledged that it is frustrating but not all that uncommon for this to happen. I am just baffled because these sensors have nothing in common with each other. No identical lot number, manufacturing dates, etc.

You are correct that my stress levels are through the roof. We had just moved to Louisiana less than two weeks before Laura hit. We are not even unpacked. I am having to spend hours on the phone completing tasks that would have easily been taken care of if we were home. While we cannot go home, we were blessed and lost nothing. So many lost everything and my heart breaks for them.



I had my first issue today. I installed my sensor but the inserter did not release and I had to yank hard to get it off.
About 15 min into warm up I got sensor error.
I looked back at the inserter and sure enough there is the sensor wire hanging out of it so the wire never made it into my skin.
So dexcom is sending a new one and wants the failed one back. So they can have it.
I wonder why you called tandem about your sensors tho instead of dexcom.


While it seems counterintuitive, if you have a Dexcom failure, but a Tandem user, Dexcom DOES instruct you to call Tandem for a replacement. I’ll see if I can find that in written form, but I have been told that on the phone when I called Dexcom Tech Support.

This link indicates that you applicator problem, among other issues, is a Dexcom call. The way I read it, however, a “sensor failure” would be a call to Tandem:

Stay safe!