Dexcom sensor change/no warm-up

Hi! New here and have what might be a dumb question about my DexcomG5. I just started using this 3 weeks ago, today was my 4th sensor change. In the past 3 weeks I have waited until the notice came up that my session ended so change the sensor. Today, I didn’t think I would be home to change it at the “right” time so I changed an hour early. When changing “on time,” it automatically goes to the warm-up period. Today it didn’t do anything except keep on monitoring. Am I supposed to do something in addition to changing the sensor?
Oh, and in all honesty, I am really, REALLY technologically challenged so please give answers in non-technical language! LOL! Appreciate any help!

You could stop the sensor, then start the sensor - that will trigger the 2-hour warmup.
Alternately (if it’s accurate as it is), you could just wait until the normal time, when it expires, then ‘start sensor’ after that.

I’ve done it both ways in the past with mixed results :slight_smile:

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Thanks! I’m assuming I just go to “stop sensor” and then something will come up to start again? As I said, it’s always been automatic and I have not needed to press anything. I’m just confused today about this. Of course, have been working all day so brain has decided to stop functioning!

TaDa!! Did it and now it’s in warm-up. Thanks again!

Are you using a new sensor every 7 days ?
This is the FDA approved and Dexcom official recommendation.

But many of us find that doing a “restart” - Stop sensor, then Start Sensor, without inserting a new sensor, provides good readings for an additional week or more, and saves money.
You will still have to wait for the 2 hours before readings appear again from the old sensor.

Search this site for discussions regarding this and experiences from others, as it does vary.


I have been changing the sensor every 7 days. The Mom of a kid my son was in Special Olympics with told me it’s possible to stretch to 2 weeks on one sensor. I wanted to get a bit used to it before I tried it, though.

I have been looking through emails - all VERY interesting!

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The best way is to reboot it, and you are good for another week.

Two weeks is pretty much standard. Many people get longer (some over 3 weeks). Essential if you are self funding.

Also, many people find they actually often are more reliable week 2 than week 1—the first day doesn’t tend to have as much of a break-in period.

Here is my discussion of

#Dexcom Hot Sensor Change

Do not "Stop Sensor"
Insert new sensor
Remove transmitter from old sensor (I just rip off the sensor to make it quicker).
Clean transmitter face with alcohol
Insert transmitter in new sensor
Do not “Start sensor”

My general experience is that you will have a dropout consistent with a signal loss, but the new sensor will come online within a half hour and won’t ask for calibration. Despite the lack of calibration, the readings are pretty darn good.

I choose to do a first calibration at “my convenience”

ps. I usually get three weeks out of a sensor. With my rate of sensor changes my sensor “hoard” should last 18 months and I now need to worry more about expired sensors.


This is all news to me, about the ability to skip the warmup. But I’ve looked on my G5 app and there’s no option to simply restart. The menu shows only four headings/options:
Stop Sensor

Are the US apps different (mine is for mmols, and from the Australian Apple App Store)?
If I’m missing something, I’d be grateful to know how to be able to restart. This morning I woke up and had to replace my sensor. I stopped the sensor, hit the button to initiate the 2 hour warmup. About an hour and 45 minutes into the warmup it was showing the countdown, but then 5 minutes ago it blanked out and I was forced to restart the warmup. Argh! A simple restart would be much better!

You wont see restart unless you stop sensor.

Hey Brian this sounds great. Don’t no how it would work. Why wouldn’t the system auto stop the sensor that is currently working a the set time. Oh well, I will try it. I don’t mind the sensor changing or calibrating. I just hate the wait time. I Already cheat on the calibrations. I cut it in half. I only test once at start up and once a day in the evening. after that unless things get freaky with readings.


FYI, my current sensor expired sometime in May, 2015 - working perfectly… though I expect it to die after its 1 week, rather than more.

I found that once sensors hit 5-6 months expired, they were noisier upon start up and basically behaved like they were already on week 3 or 4. So they are better than nothing, but not great. Made me decide to go off automatic reordering for my Dexcom and to avoid accumulating such a big stash again. Of course, YDMV.

My second-worst experience with a G5 sensor was today (my first sensor was installed Sept 2017): it died just prior to the end of the 7th day. I got the dreaded ??? within minutes of a crazy-looking graph about the time I woke up this AM. I’m not calling Dexcom for a replacement, as I have enough sensors.

My worst was a sensor that I removed after roughly 2 days (and got a free replacement for it).