Tslim x2 malfunction

I experienced my first major problem with the Tslim last night. I had just put in a new g6 sensor and sat down to watch a movie. About 10 minutes later, my pump alarmed and displayed a malfunction message that the pump could not operate, and gave a code. I do not remember exactly what the code was other than that it started with a 0.

I called the helpline and they said that it was a software problem that could not be reset and that they would send a replacement. When I asked why the error happened or what could have caused it, they did not have any information to provide, other than that the pump had determined that it could not deliver insulin safely. Does anyone have any experience with this or have any idea what could have caused it? Needless to say, I would like to prevent future occurrences if possible.

The only possible thing I can think of is that I went to a kickboxing class that morning. My pants had no pockets so I clipped the pump to my waistband, facing inward with the screen against my skin. I did get sweaty and hot in the class but it was only 45 minutes long. There was a sheen of sweat on the screen after the class. Could this have had anything to do with it?

In the meantime, I’m super thankful for my old Medtronic pump that I kept as a backup!

Sweat is not a problem. But facing the Tslim into your body is. Bluetooth communication is totally blocked by the body. People sometimes experience that when they lie in bed in such a way that the body blocks the radio communication from Dexcom sensor on the arm to the pump. This may have caused the irreversible error. Just speculating.

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You cannot prevent software problems. Those are beyond your control.

Kickboxing class would likely result in a hardware problem - pump getting dislodged from the tissue or pump getting smashed. That’s a different type of problem.

If you save the code, you can google it. People have accumulated lists of those error codes. It’s too bad that they didn’t give you more information, but next time you get an error code (which could be years from now) - keep the error code.

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I did have a thing years ago where my pump crapped out after a bike ride in very hot weather when it had got very sweaty due to carrying it in that little inside pocket of my exercise shorts. Button freeze. But that was an old Paradigm with mechanical buttons. The TandemX2 spec says it’s water-tight (not water proof) to a depth of three feet for up to 30 minutes. So I doubt that’s what caused your problem.

It is disturbing as a Tandem user to know it can suffer a fatal crash, but I guess that’s a possibility for any software. It may also be that, because it’s a life-critical medical device, the protocol doesn’t allow for any software recovery procedures and a software glitch just means the whole thing has to be replaced for safety reasons.


I have had 2 failures in 3.5 years on X2. In both times, Tandem support walked me thru a process that reset my pump and cleared error. The most recent was when starting a new G6 transmitter. I put in trans id, but it was rejected. After calling tandem support, they had me do a reset, and newer software loaded. Then the transmitter was found/paired.


The person I talked to said that some errors can be reset and some cannot. Mine was an error that could not be reset. That is the entirety of the information that he had for me.

Meanwhile, this happened on Friday evening, and I’m still waiting for my replacement on Monday, late morning. I know that it was a weekend, but I was surprised that they could not get my replacement to me sooner. I live in a major metropolitan area. I have several issues with Medtronic as a company, but one thing I can say for them is that whenever I needed a replacement pump they sent it overnight regardless of the day of the week.

My MT pump failed on a Friday and they could get me the new one only after the weekend, like three days IIRC. That was a while ago though, so I’m glad to hear they’ve improved. It did teach me to appreciate the fact that every year my Endo prescribes a box of Lantus and Fiasp pens to have on hand in case of pump failure!


I’m an engineer. I expect any mechanical or electromechanical device to fail. I expect software-based devices to fail more frequently.

I’ve been prepared and waiting for my first system meltdown since the day I received my t:slim x2 pump. imo Any competent adult who depends on an insulin pump but isn’t prepared to revert to MDI at any time is courting disaster.

You can not schedule equipment failures and can not rely on an uninterrupted supply chain.

I know from the past year that I can’t count on the insulin I use being in stock at a pharmacy that’s open. Sometimes it takes more than a week for my 90-day order to be filled. So I maintain a 30-day supply buffer as insurance. I do similar things with all my essential supplies.

Within 16 months I experienced two pump software errors that were fixed by resetting, and one that was fatal that required a pump replacement. I received a replacement pump the next day before noon. If it had happened on December 30th, I might have been without a pump until January 2nd or 3rd.

When I was about to go on an extended trip I called Tandem and they shipped a backup pump to take with me. On my last 3-day trip I didn’t take a backup pump, but experienced a G6 sensor failure during the second day of wear. I replaced it with one of the two G6 sensors I brought with me.

It’s better to be over prepared and later feel foolish than to be underprepared and later feel desperate.

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I’ll bet you also wear suspenders with your belt. :rofl: :joy: :upside_down_face:


Yes, I’m pretty conservative when it comes to preserving my life. I’m 76 and have 20:25 hindsight. It tends to happen with most folks with increasing age or experience. My Dad was an exception. He died of complications of T1D at a much younger age than I am now, blind for the last 10 years of his life, a burden to my Mom for +20. An “iron man”, he couldn’t get past denial and anger until it was too late.

If I hadn’t been scared by my prognosis of “20 years - if you’re lucky”, and started becoming super-conscious about managing my T1D after a bone infection and proliferative retinopathy +30 years ago, I wouldn’t be walking, or driving, probably wouldn’t be alive, today. My jobs had increasingly unpredictable hours -on call 24x7. More than once I was called on a weekend to locations where there was no place to get food. Once I had to work 2 days straight through a weekend - alone. Being prepared for anything was the only way to survive.

Retired now, I do occasionally wear a belt and belt-support suspenders when I’m wearing tools and have to do something requiring bending or climbing, and I can’t wear tight fitted pants.

What you think of as belt and suspenders for T1D -reserves, backups and redundancy - is not just basic common sense, but is included in the manuals for the advanced tech like insulin pumps. Every critical system needs reserve capacity, backups and redundancy. Ones that don’t have these fail often and need to be frequently rebuilt or replaced at high cost - like converging expressways or “good enough” bridges. When they fail they cripple the function they were suppose to serve.

I’m a technologist. I hate having to “hack” at an appliance to figure out how it is supposed to work. I curse those who embed a computer in an appliance and then don’t document it in a manual. “Updates” isn’t a reason to not document. . That’s a CYA excuse used by lazy designers for not documenting a bad design. Products that are well engineered for their purpose are either very basic simple tools that can’t be used incorrectly, or they aren’t. (There are schools that teach people how to use hammers and knives.)

It’s a pity that, even when good manuals are available, folks are being conditioned to hack their way through learning about advanced tech. If more people would read the manuals and books that are available free, and think, before asking total strangers for easy answers, I believe everyone would be more productive.

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I am 82 years old and live in the boonies where the closest town is 20+ miles away. Have been living here for 35 years taking care of my incapacitated husband for 30 of them. My grandmother had diabetes and died at 72 in a nearby foreign country after taking one insulin shot daily. But that was in the 1950s. I know all about working 36 hours straight in my “previous life.” And I agree about appliances and other “technology” not coming with any manuals free or otherwise. Have had to go online for “how to’s” to fix them myself more times than I wish. But one cannot obsess about these things. I can revert to simple MDI when needed and, while it is inconvenient, it is just a reminder of how good I now have it with my Tslim with CIQ most of the time. I, too, find that technology isn’t documented enough today. But one has to plow on as best one can. Otherwise, life becomes one long tribulation.


Thanks, pstud, for your response. I appreciate the insights of those who are older and/or have more experience than I do. (Though I myself also have over 30 years of T1D under my belt and have used several models of MT pumps, Tandem, CGMs, and MDI).

I was under the impression, though, that the point of this forum is to ask others for advice. While I do admit that I could have spent more time looking at the manual before posting this question, I have gained so many useful tips and insights from this forum in the past, that I thought it wouldn’t hurt to ask. If this is the way you feel, you are under absolutely no obligation to respond!

At any rate, thank you and to everyone else for your responses. I really appreciate them!


I’m glad you’re picking up tips here. I think that’s a main purpose of this forum. I live in Ontario, so I don’t need a prescription to pick up insulin from a pharmacy, which I really appreciate during an emergency situation. One time, I was going to Niagara-on-the-Lake to see a play. I showered, got in the car my friends were driving, and didn’t realize until I was an hour away from home, and almost at the venue, that I had forgotten to re-attach my insulin pump! I was so angry at myself for doing such a stupid thing and although I know my friends would have missed the play and been gracious about taking me straight home, I just didn’t want to do that to them. Anyway, I had my friends pull off the highway, went to a drugstore and bought Humalog and some syringes. I kept micro-dosing until the play was over, and I got home. I managed my BS pretty well, so it was ok. I’ve also had incidences where I’m far away from home and accidentally rip out an infusion set and not have another in my purse or car for backup. (I’ve done that at work or on a day trip.) Pharmacies might have infusion sets, but they never have the ones that work for me, so I buy insulin/syringes at a pharmacy, wherever I am. I make sure now that I have backup infusion sets in my purse. Hardware and software problems, however, can’t be predicted or anticipated, so that makes it extra difficult if you’re out and about, but do always have insulin and syringes at home for backup if the pump fails there.


I had this happen recently with my Tandem - an error that Tandem said couldn’t be fixed. However my pump was out of warranty, and I didn’t have the funds to replace it immediately, so I did the “hard reset” I found online (which the support guy told me was a possibility, but that he couldn’t advise it).

This worked, but then failed again a couple months later, when I decided to put the copay on my credit card, and got a new one! (I was able to do the “hard reset” again to keep it going til my new pump arrived a few days later)… I won’t let it get out of warranty again if I can help it.

and this is totally the place to bring up something like this - thanks!


Good to know that this exists, if I’m ever in this situation (which I will of course, try to avoid!). I’m glad that you got it working again long enough to receive your new pump.


I have been using my X2 about 1.5 years. I recently had 2 unusual failures:
About 3 weeks ago had a weird problem.
Pump Battery was at 70% before new Sensor, plugged in charger. After new Sensor inserted, Battery at ONLY 10%!!!. Reconnected Charger and cable, now slowly charging.
At 10:00 pm was at 25%, but got error “pump can not be charged by current source, please replace source”.
10:13 pm went to plug in new source, but now shows Battery is 100%!!! Reported to Tslim support.
Last week:
Wed 2:50 pm New CARTRIDGE, TUBING & Cannula (filled syringe to 190).


I “replaced” the Cartridge I just installed a couple hours ago, let it pump out the 10 min units it wanted, then called TANDEM TS.

They verified date, time, etc., told me to “START SENSOR” BUT SELECT NO CODE, then wait 15 min. In a few minutes it showed CGM again! Support guy said he documented, said if happens again will replace pump.

I have generally been very pleased with the X2, coming from a Medtronic 670G.

I hope it’s ok now, but if need replaced, should happen overnight.
I ALWAYS keep extra syringes and Insulin on hand.
And I still have the 670G with infusion sets and Insulin reservoirs I can fire back up until I get a replacement.

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