Easier way to restart dexcom wo removing transmitter

Hey everyone, for those who restart your sensors, I discovered an easier way to restart where you don’t need to remove the transmitter.

I stumbled on this accidentally. I was changing out my transmitter. I forgot to put the new transmitter code into my pump and I started the sensor.
Obviously it didn’t work I got an error.
So I stopped it then I changed the transmitter code and tried to start again and it worked.

So when that sensor was finished I tried to repeat it.
If you follow these steps you can restart sensors.

  1. Wait for the sensor session to expire
  2. Change transmitter ID to an old one or anything. ( has to be a valid ID though you can’t make it up)
  3. Start new sensor. The pump or phone will not be able to find it and will error.
  4. Enter the correct ID for the transmitter that is installed and start sensor.

It will come on just like normal.

No more prying it out , which I could never do because I wear them on my arms and I can’t see it, well enough to get it out.

So this is the second time I restarted a sensor with this method.
I will keep this one going if it’s behaving.
I generally don’t restart sensors because I have insurance and it’s a hassle, but now I might do it once in a while


@Timothy , this is more for the rest of the folks since you are a long time ‘resident’ here at tuDiabetes. This is about wearing a Dexcom in locations outside those approved in writing to the prescribing endocrinologist. The patient should have a copy of the letter approving the variance based on significant research. Most of this was shared by my endo’s pump team.

In early 2021, another placement reared itself. Child protective services were involved with a child after an unrelated emergency room visit for a trauma event. The CPS notice indicated an ER doctor notified CPS because the pump (brand not specified) & Dexcom were not placed according to standards. The conjecture related to placement is wide open. Take away, would site & sensor placement pass CPS scrutiny?

The rest of the information:

As far as the CGM sites are concerned in the USA, using a site outside those approved by the FDA following Dexcom research and development place you in peril of footing the bill if you lose a wire. Sure, G6 is approved in other countries for other locations beyond the abdomen. Here in the USA, you are limited to the belly.

Here’s why. From what is written about the way FDA does approvals, we are still in the post-thalidomide tragedy mentality of the early 1960’s. To some this may seem harsh, yet it is true. The US Congress and American people supported a “never again” mentality will anything be approved unless it is safe. The cases of phocomelia were horrible. Some say this is strong language, however, it is still used today in language related to FDA rationale, power, and need for authority.

Here in the states, everything must be checked and double checked and scientifically proven to be safe. Who knows, until proven otherwise, the placement of CGM sensor wires in the upper arm may provoke the growth of new hands in the upper harms (NOT).

The understanding the regulatory process is, if a prescriber wants to use something in a manner different than approved by the FDA (called off label), the prescriber must write to the manufacturer, describe the situation, and request off label approval. Many people are told by their prescribing doctors, “Oh, just go ahead and do it.”, not realizing the Pandora’s box which may be opened in a misadventure. I have seen local newspaper coverage in days past of malpractice lawsuits shining the light on such issues.

The purpose of this group is support. Sharing published regulatory & usage information is a form of support. Providing information from contradictory, inapplicable, & unfounded sources without substantiation is not supportive & may in the opinion of others be an undermining of veracity.

In regard to claims about sites, it is the savvy claims clerk in the insurance company that creates the problems related to off-label use.

When a claim comes in for the removal of a wire from, hypothetically, posterior upper arm, and the insurance clerk notifies the hospital or doctor making the claim, additional information is needed. What type of wire? If the response is a Dexcom CGM sensor wire, the clerk checks to see if the device was being used according to published standards.

If the device was not being used according to published standards, the insurance clerk should deny the claim as ‘device not used as prescribed’ (because the prescription is for an FDA regulated device to be used according to FDA authorization). Failure to use according to directions, without variance, constitutes negligent usage, placing the onus, and therefore the bill, on the user.

The point of my post about ‘proper placement’ is not what the patient would tell anyone. It is what the health care bill to the insurance company would reveal and the sequelae.

One additional item to remember is being told by a prescriber it is permissible to use an item outside FDA authorization or ‘off label’ in the case of devices requires the device manufacturer to be notified and acknowledge the variance in writing according to the FDA.

Anyone in this situation should verify and obtain copies of correspondence their physicians have had with Dexcom seeking approval of off label locations and the clinical reason for the requests.
The mountain of off-label requests will be the only impetus medical device manufacturers have to re-open the approval process and divert resources to current product situations. In the meantime, inspection of medical device companies’ prospectus (yes, the plural of prospectus is prospectus - see Oxford Dictionary) will show major investment in R&D (new product research & development [FDA required testing, etc])

BOTTOM LINE: As informed users of ‘restricted medical devices’ (restricted medical device includes but is not limited to a device & accessories requiring a physician’s prescription), we the users must learn the “Thalidomide era” safeguards and apply those same rules to have common sense brought to the forefront. Here is the link from the Dexcom website (make sure you are on the USA page):

Where can I insert my Dexcom? [link is for USA – country selection is in upper right of screen]

As an additional regulatory oddity, this is the same as connected INSULIN PUMPs on airplanes. I have yet to find in FAA regulations the full approval process demonstrating insulin pumps are safe to use on commercial aircraft and that the radio waves generated, or electromagnetic interference (EMI) will not cause the plane to crash. Twenty year ago, when CGMs were first making their appearance, there was rattle about the radio waves from the CGM transmitter being in the same frequency range as some important avionics. Use of items operating in those frequencies were unproven and deemed (by FAA regulation) dangerous until proven safe. (one of the reasons given 20+ years ago when I started pumping).

This is a long post. The picture is big. Let’s pull together and get the eyes opened so location in one country is good in another.

Hope this provides the sunshine needed. The comment is to illuminate the situation.


Well at least the g7 will be approved for behind your arms.
And we’ll I would never attempt to hold dexcom responsible if I use the sensors in a different place.
The reality is that they work better for me on my arms.
As for off label use, I’ve been doing this for a very long time.

I used third party infusion sets, I used enlite sensors in my older Medtronic pump.

I created a union so that I could get dexcom data to show on my Medtronic pump ( not integrated for looping) this was before the loop algorithm was around.

Really we need to figure things out so we can best take care of ourselves.
Yes there is some risk if you don’t know what you are doing.


You discovered something awesome! Thanks for sharing it. I enjoy saving money on my co pays by restarting G6 sensors and will try your method next time. The big picture is my insurance company saves money too if I can use fewer sensors over the long haul.

My experience has been some sensors will go for many additional days after a restart but more often a restart only gains me a day or two. I’ll keep trying though and appreciate you sharing this method which seems easier than the “pry out the transmitter” method. One thing I like is it can be done after the sensor session ends, makes it easier to work it into my schedule.


@Timothy , you are more than 100% correct. We must go to bat for ourselves, share our successes, and publish the potholes so others may travel safely down the highway of D.



When you say ‘transmitter code’, are you referring to the transmitter serial number or the ‘sensor code’? They are two different numbers.


Good catch, @Mayumi. So, @Timothy, did you mean to say “enter the sensor code”?

I have been using Dexcom for 14 years and it has been my experience that some sensors last the usual time and sometimes my restarts have lasted as long as 29 days total.


Woohoo @Timothy I will have to try it next time! I get about 25 days from each sensor, sometimes less, sometimes more. I like the front of my arms because I can see it easier to change out the transmitter so this method will make it easier to vary it’s spots!!! I like a restart better as it is easier to get it in line with only being 5 points off after a restart. A new one can take a few days.

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I meant that you put in an old transmitter code.
Wait for it to error either because it is expired or the system can’t find it.
Then enter the transmitter code from the good one, the one that’s still in your sensor.
Then you can start the sensor as you would a new one
And then You enter the sensor code as you normally do, hopefully you still have the little tab with that info


I’ve read a few posts, that they take a picture of the “code” on the sensor, before throwing it away.

I just started the G6, after my seemingly endless supply of G5s ran out, and I’m using the no-code method. I wonder if the restart process you came up with would work with the no-code way? I just changed my sensor, so it’ll be a bit before I can test that theory, but someone else might want to give it a try :slight_smile:

Great find @Timothy !! Thanks so much for sharing!

I’m sure the no code method will work. I don’t see why not.
But tell me why you do that.
It seems like you will need to calibrate twice a day with the no code method and you don’t need to calibrate at all with the code, of course you can calibrate anytime if you want to.

I’ve followed a lot of posts on the G6 to prepare myself for when I would move to it. What I read was saying the no-code method prevented a lot of problems for when you did need to test/calibrate or problems with highs not high or lows not low. I’m used to testing and it doesn’t bother me to calibrate. I guess too, until I’m a bit more seasoned without needing to test, it a comfort measure :slight_smile: to test


Ok well, like I said, using the code doesn’t prevent you from testing and calibrating. It’s just means you don’t have to

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I read that, too… But man, has my experience with no-code restarts been different. I’ve tried it twice, and both were complete nightmares with errors and the dreaded calibration loop where it rejects every value I feed it. There seems to be some expectation already built into the system. It’s not as receptive as I was lead to believe. I think the codes just provide subtle tweaking.

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I haven’t experienced a restart yet. I haven’t tried. I think this might be my forth sensor and second transmitter (a failed transmitter prompted dex to send me a new transmitter and new sensor). My experience hasn’t been the greatest; the g5 was nice, just a few problems in as many years, but I really liked the g4 and as accurate as the g5. I’m on the fence with liking the g6. I don’t like the receiver. I only use it, not a phone or watch. But, I’ll continue with the G6 until the G7 is out in hopes it is better.


Transmitters don’t have codes, they have serial numbers.


Interesting. I understand this is about entering in a different transmitter serial number but has anyone tried entering in a different (valid) sensor code? I used to think the sensor codes were tied to the actual sensor but now I’m not so sure. I recently was talking to a Dexcom tech guy and I asked him what would happen if I accidentally entered in a wrong sensor number and he said it wouldn’t work because there are only a few set of numbers that they use for sensors. So it got me wondering if the sensor code is only used to activate the sensor and has nothing to do with the actual calibration of the sensor. Does anyone know?

The sensors and the transmitters are totally separate.
The sensor wire is treated with a reagent.
That reagent binds to glucose and creates a tiny micro current.
That current is transmitted to the pump or phone exactly how it is without adjusting it.

Your pump or phone will apply the calibration that you performed, or use the calibration code to convert the micro current into a concentration value.

So although the transmitter is paired with your phone and pump, it’s really just a non thinking link to a receiver.

You need the transmitter ID only so the receiver knows what signal to accept, and not pick up someone else’s who might walk by.

The calibration works simply.
A large batch of sensors are made at one time.
They pick a few and test the micro voltage that comes off.

Then a code number is assigned. So maybe 0.35uV is what it tests at but they want it to be 0.40uV.
So a calibration adjustment is applied +0.05 and a code is applied. Say 1234.

Then when you install the sensor you put in the code 1234 and it knows to adjust +0.05 uV to the value it receives from your transmitter.

A different lot has a different code . The next one might be -0.3 and so it will subtract that from the value it receives.

That works exactly the same way when you manually calibrate.

They use limited codes so you won’t likely enter the wrong one, but you could. If you enter an old code, it wouldn’t t know the difference but your results would likely be off


Wow, good info. How in the world do you know so much about this stuff?

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