Dexcom transmitter or receiver problem?

I changed my sensor and inserted a new transmitter Sunday. They never paired. Got a transmitter not found message. I called Dexcom and waited on hold for 20 minutes and then requested a call back.
Waited 3 hours and no one called me back. I called again and waited 10 minutes and finally spoke to a live agent. She said to try again even though I was trying for hours and said she would call me back in 30 minutes. She never called back. I waited 2 hours and after being on hold for 30 minutes the agent said he would send a new transmitter. It arrived Tuesday. I inserted the new sensor and transmitter and got the same error. Transmitter not found. I called Dexcom and was told it must be the receiver because it is near impossible for 2 new transmitter to be faulty. Now I am waiting for the new receiver.
Has anyone had this problem?

Did you change the transmitter serial number inside the reciever? I always forget to change the serial number inside the reciever. Thats he only reason that I’ve ever gotten that particular error.

Step #3 min 1:40…dexcom change transmitter id inside reciever - Google Search

If its not this problem, then I would agree that its probably the reciever.

Yes, I put the new transmitter SN into the receiver. I tried doing it with only the receiver several times and only my IPhone once.

In a message dated 5/13/2020 11:35:49 AM Eastern Standard Time, writes:

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On receiver, did you check settings and see transmitter id and battery status? Maybe it had already drained, or had bad batteries to begin with.

On the receiver the only info it gives me on the transmitter is the SN.
It never paired so never activated. Dexcom tells me that almost impossible for 2 new transmitters to be bad so must be the receiver?

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I’ve never had a reciever go bad. This is an unusual error. Good to hear about it.

Does the transmitter id have a zero or one, that could really be letter O or letter I ? If yes, try switching what you entered. I think I had an issue like that with a G4 transmitter.

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No zeroes or ones. I even tried the option of taking a picture of the SN with my phone and still got transmitter not found error.

Dexcom support is the very, very bad. I am sorry for you experience.

I got through yesterday in 2 minuites. Someone else suggested calling 1st thing in the morning. That worked, unless I just got lucky.


I’m sorry to hear that this has become such a battle for you.

I have a long-shot (that is probably not very likely) suggestion for you.

In particular, I’m wondering whether you have ended up with a newer “series” transmitter that is not supported by an older version of the receiver software.

For starters, Is this a G6 receiver and transmitter? If so, I believe that the transmitter serial numbers start with 8G, 8H, 8J, or 8K. I believe that the newer series (8J and 8 K) must have different software than the older 8G and 8H because others report that is is increasingly difficult by design to restart sensors beyond their 10-day limit if they are using newer transmitters.

Are your new, problematic transmitters 8J or 8K and have you been using older 8G or 8H until now?

What is the software version on your receiver? If you post it, others can likely comment on whether that is what they are running or if they are running a newer version of receiver software. I use a t:slim as my receiver, so can’t tell you what Dexcom receiver software versions are and I have been unable to find that information on the Dexcom website.

As I say, this may not be a likely scenario, but I offer it as something to check out.

Good luck.


I have been on the G6 sensor since Jan. When I got the G6 they told me to continue to use the receiver I had been using.
The software version is firmware 5.1.022
The two new transmitters are 8K and 8L
I have had no problems with the G5 or G6 until this past week.


I actually received my G6 stuff in early January, but didn’t begin to use it until about the first of Feb in order to build up a “stash” of sensors in case of monthly Medicare shipping delays. They sent me a new receiver at that time because my G5 receiver was one of the non-touch-screen ones.

I found that I have my receiver with me … even though I don’t use it because I use my t:slim as my Dexcom receiver. I tried to fire it up, to see if I could learn what software version it was running … but couldn’t get beyond it wanting to pair with a transmitter. I tried entering a bogus number ( because I don’t want to disable my t:slim ), but that didn’t work.

Hopefully, someone else can tell you their receiver software version.

In the meantime, if it would help you, I could overnight you my receiver to see if that can get you on the air. If that is of interest to you PM me your mailing address and I’ll try to USPS overnight it to you so that it would, hopefully, arrive on Saturday.

Good luck … I’m sure you are hating life without your CGM.


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Thanks, John, I appreciate your offer but I am supposed to get my new receiver tomorrow. I find it odd that Dexcom overnight orders take 3 days yet I ordered some Immodium yesterday and I got it today. I have been Type 1 for 32 years and have only used the sensor for 18 months but feel lost without it.

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I hope the new receiver gets you back on the air … I know how unpleasant it is to be without CGM.

I’ve beenT1D for 48 years … but only on CGM for about 7 years and pump about 5. Hate to be without either …

I can’t figure out Dexcom overnight either. The one time, however, when I really needed it … they came through:

I had a transmitter failure on President’s Day in Yellowstone National Park. I called near closing time from the Mammoth Hot Springs Hotel near Gardiner, MT that evening … and the transmitter arrived by noon the next day!!! Wow!!! Good thing too … the morning after that I left via snowcoach to spend 8 days in a yurt camp near the Grand Canyon of the Yellowstone where they have no electricity, virtually no cell service, and no WiFi … and certainly no FedEx.

Needless to say, I was more than happy to head there with a new transmitter. Being 3-5 hours by snowcoach from the nearest (minimal) emergency services was no time to be without CGM …

I hope that by this time tomorrow, your CGM is running and you are already complaining about the annoying alarms …

Stay safe!


Got my new receiver today. Everything working fine.



Stay safe.


My receiver is from 12/2019. firmware 5.1.1… SN MX94…
New transmitter of a few weeks is SN 8LG…
They paired without problem.
Edit: Oops. just saw you got it fixed. Great!

Well it happened to me last week. Thought the same thing till I took the transmitter out and reinserted. Realized I had put the wrong end in first. These things are very touchy. When I heard the snap on the 2nd insertion I knew it was good. Just FYI