Help with T:Slim and Dexcom G6

Hi all, I’m a new member of tudiabetes and could use some assistance from other users of the tandem x2 pump and Dexcom g6 combo. I switched from my beloved Minimed pump (was on a Medtronic pump for ten years) to tandem 5 weeks ago so I could take advantage of the BasalIQ technology that the tandem/Dexcom combo offers. But my experience has been awful, such that I regret switching…the problems have been numerous: pump loses battery life in less than 48 hours (I’m already on my second pump, and it is doing the same thing as the first), and I’ve had multiple bent cannulas (one causing major blood sugar spike; had to change that site 3x in one day). I just changed my Dexcom transmitter site and entered the code, and I am receiving errors that I have an invalid transmitter ID. I do not have an invalid ID, and I didn’t change the ID in my pump. I have no idea how to fix this…and it seems that Tandem doesn’t employ customer service staff during evenings and weekends (despite their 24/7 claims and the offer to enter your tel no so someone can call you back…no one calls back. The first weekend I had a major issue with the pump, I called six times on Saturday, multiple times Sunday, left my number for a return call…and didn’t reach anyone until Monday. Right now, I’ve been on hold 45 minutes and haven’t reached a human yet. If I had known how awful this company/technology would be, I’d never have left Medtronic (despite my love for Dexcom), and now I’m just stuck and furious. But that is beside the point…how do I fix a transmitter ID issue with this pump? Any assistance would be GREATLY appreciated.

Sorry you are having these problems.

Dexcom has separate Technical Support, available 24x7

US Dexcom Technical Support
888 738 3646

Or fill out request at

Not sure if Dexcom support would help, or send you back to Tandem.

Are you saying you put in a new sensor, then attached same transmitter, then entered 4 digit sensor code ?

One idea is stop sensor, completely delete existing trans id, reenter trans id, then start sensor again, with code.

Tandem Technical Support is 24x7 while Customer Support is not. Be sure you are choosing the proper option in the phone menu.

As @MM1 says, Dexcom Technical Support is also an option perhaps for some of the issues you are seeing.

Dexcom insertion and within the two hour warmup window are typically handled by Dexcom. Once outside the 2-hour warmup and when the G6 is integrated with the X2 then Tandem picks up those support calls.

Can you elaborate on what you mean by pump loses battery life in less than 48 hours?

Aside from the pump, do you also use a phone to receive the Dexcom data?

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Hi MM1, thank you for your reply. I misspoke - I did call the 24/7 Tech Support line, not customer support. Someone did reach out to me about 4 hours after I left my telephone number, and they suggested the same steps you did: stop the sensor, reenter the transmitter ID, then restart the sensor again with the code. Unfortunately, I subsequently received an error message on my pump that said “Replace Sensor Now. Sensors can only be used for one session…” Which means I wasted a brand new sensor (having inserted the new one that evening).

Tim 35, thank you also for your input. I’d heard that Dexcom tends to refer T:Slim users back to Tandem for any issues with the CGM/pump combo, but I may try calling them next time to find out for myself. Dexcom has always had such good customer support. As for the battery life, both T:Slim pumps I have used in the past 5 weeks (the original and the replacement) have eaten through a full battery charge in less than 48 hours…in 24 hours, I frequently go from a 100% charge to a 45% charge; on one day, my pump battery dropped 20 percent in one hour. On another day (when I hadn’t charged my pump in the morning and was relying on the charge from the prior morning), I received an alert saying I had 5% battery life left, and it completely freaked me out - I wasn’t at home and had to drop what I was doing to rush home before my pump stopped working…and then sit attached to a charger for more than an hour to restore full battery life. After those two incidents, Tandem did replace the pump, but most days the battery on the new pump decreases by more than half in 24 hours. This is especially worrisome because I live in a state that tends to get hit with hurricanes each summer, and losing electricity is a strong possibility…I’m going to need to make sure I have a whole lot of battery backup systems on hand because I cannot trust my pump to last more than two days. When I search online to see if anyone else is having this issue, however, I don’t find any other complaints…so this is just my bad luck?

Oh, I do not use a receiver to get Dexcom data, and I sometimes use a phone to get the data. Do you think that may contribute to the short battery life?

Insertion issues and within the 2-hour warmup are supposed to be handled by Dexcom.

I have also gotten Dexcom to pick up sensor issues (well past warmup) that did not make it the full 10 days such as sensor failure on Day #5. We also use the iPhone to receive the data so I only spoke of the iPhone and did not mention the X2 pump. They did not ask. So they handled the issue.

But normally if Dexcom knows you are on the X2 and it is past the 2-hour warmup then they will foward you over to Tandem Technical Support.

Sometimes Dexcom Tech Support is faster and sometimes Tandem Tech Support is faster. So I go back and forth between them. Last couple of times, Dexcom Tech Support has been faster for me then Tandem Tech Support.

Couple items I would mention.
In terms of replacement, I would not discuss the 45% with Tech Support.

  • Time how long it takes to go from 100% to 5%. Discuss THAT with Tandem Technical Support.
  • The X2 pump battery is supposed to last 7 days when NOT integrated with the Dexcom and 5 days when it IS integrated. Plus or minus a bit. But close. 2 days is NOT close.
  • Using a Smartphone (or not) as a Dexcom receiver of cgm data has no impact on the Tandem X2 battery life. Zero impact. We use the iPhone and X2 to receiver the cgm data and it works really well for us.
  • You do not have to use the charger/cable supplied. Nor rush home. Charge the X2 in the car or from a portable battery on the fly. I strongly recommend you get a small portable battery and carry it with you particularly if you are having battery issue and intentionally want to run the X2 down to 5% battery to time how long it takes. I would actually get two of these. So, when one battery is recharging, you have the other fully powered and ready to go. Get them in two different colors to make it easy to keep track of. Regardless of what the X2 manual or Tech Support says, we recharge the X2 from these batteries all the time. And from the car usb adapter. And any usb adapter around the house. My suggestion for a good, small cheap usb battery:

Anker 3350 mAh “lipstick” sized
3 ounces
comes in colors Black, Blue, Pink, Silver


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One thought: there’s the transmitter (which lasts three months) and that you keep using and don’t change the code when you start a new site and then there’s the sensor where you enter a new sensor ID each time you start a new (10-day) sensor. Perhaps you already knew that and I apologize if this is redundant. But, anyway, when you have a new site you shouldn’t have to do anything to the transmitter ID.

Hi Tnyc, thanks for your comment. Last night I inserted a new sensor (the 10-day one with the four digit code)…my transmitter is not even close to the three month expiration date, and I hadn’t touched my transmitter ID in my pump, but the error message applied to the transmitter ID, not the sensor code.

Tim35, THANK YOU - these are great suggestions, and I appreciate you sharing your real world experience about charging your pump. I think I will get some of those battery chargers and actually test (intentionally, not accidentally) the lifespan of the new pump.

I reached out to Tandem again this morning to request a replacement sensor, and they said that, per its agreement with Dexcom, Dexcom would need to provide the replacement sensor. So Tandem forwarded me to Dexcom, which said that, per its agreement with Tandem, Tandem would need to provide the replacement sensor…at which point I asked Dexcom to please not bounce me back to where I began, with both companies disclaiming responsibility. Dexcom, to its credit, is sending out a replacement sensor for me.


Using any charger that you have may not work well. I had a continuing issue with my X2 where U would charge it for a couple hours until it said it was 100%, then I unplugged it only to find a couple minutes later that the pump was at 5% charge. After a fairly lengthy talk with DexCom tech support, we concluded that the problem was that my Kindle charger didn’t put out enough amperage to charge the t:slim, only enough to fool its electronics. Since then, I’ve only used higher-wattage chargers (iPad ones) with no problems).