Dexcom sensor restarts: microwave trick and 2-hour restart



I haven’t tried it, but my guess is that if the receiver says the session has ended, it’s too late, because the phone would already have been told that too. It’s possible that even 5 minutes before the session ends would be ok, just so long as none of the devices have been told that we’re in the warmup period. But this is all pure speculation on my part.


I would think it needs to be at least 2 hours and 5 minutes before, right? Otherwise the phone knows it has ended also.


That is correct.


I ordered a Farraday bag so I can try this with my Tandem pump and phone. Either way, I will post the results.


Now THAT one is sounding interesting. Might need some pics.


I just changed a sensor this morning. I stopped it on the phone, put the transmitter in the new sensor, and immediately ( within 5-10 minutes) started calibration. My watch didn’t miss a reading, although the first one was 374 and the second 52. Then it all settled down.

I do this every time. Works great. Oh, I use xDrip+ with the watch as receiver.

Am I a smart ass, or what?


@docslotnick smart-something…lol


I would say you should just build a small faraday cage, but $9 is pretty cheap.


I just did this. It works without a problem. And you can actually calibrate on either the iPhone or the Dexcom receiver. It works either way.

When I went through the 2 hour warmup, I simply put my receiver outside at the end of the driveway. Didn’t need any extras to get it done.

All that being said, it reminded me of this:


Once you hit stop/start on the receiver what about simply turning the receiver off for 2-hrs?


I don’t think that would work. The countdown is happening on the receiver, not the sensor.

But hey, trying it is free! Maybe next time I can do that and see.


Although true, my question was more along the lines if the countdown continues while the receiver is powered down.

Is it really the minute by minute countdown which is relevant or the fact that two hours have passed? With the receiver powered up this is the same thing. But turning the receiver off in the middle turns this into two different things.

I consider it entirely possible for this to work with the receiver powered down. I would try it myself but on my last test, I hit the message about this is the last restart allowed on the transmitter.


That will not work (not 100% sure, does not hurt to try)


I never shut my receiver down. Ever. I’ve had three receivers crap out after being shut down, so mine never get turned off for any reason.


The issue with turning the old receiver off comes into play during initial BLE pairing and is not relevant at all with the new receiver.


Next week after we are on the new transmitter then I will give it a try. No downside.


well so we weren’t able to restart the sensor more than two hours before the restart because Samson was at daycare. We only managed to put the receiver in the microwave 4 minutes before the sensor session ended – and sure enough it required a restart on the phone. So next time I’m going to try it more than two hours before the restart.


I am an audiologist and have seen many pictures of hearing aids that ended up in the microwave due to people reactivating a pack of desiccant but also stupidly putting the aids in the microwave… ooooops :wink:


It’s an issue anytime you’re changing out the sensors. I reported on it back at TuD when it first happened to me and many others have also received the error. It’s called an “ERR 121” error, and it’s very relevant. This error is what caused me to discontinue ever shutting down my receiver. Not sure what causes it exactly and the Dexcom technical support staff wasn’t able to answer it either, but they indicated they’re advising folks to just not shut it down if you can avoid it.


As mentioned, not relevant with the new receiver.