670G sensor issues

I use the 670G pump and I absolutely love it! It has controlled my diabetes and lowered my A1c. The only problem is I have trouble with the sensors. When I insert one, it works for two out of the seven days. On the second day, my pump will say “Updating sensor do not calibrate” and this usually takes 3 hours. After that, it says replace sensor! It’s frustrating because this happens almost every time I insert a new sensor. I’d like to be able to use auto/manual mode because it helps control my sugars better. Am I doing something wrong when I interest the sensor?


Have you called Medtronic about these problems? Tech support can be a hassle, but even if you get a rep that is bad at troubleshooting, they should replace any sensor that doesn’t last 6 days.

When you remove the dead sensor, is the filament bent? That could indicate insertion error.

Have you tried different site locations? Abdomen and upper arm are approved areas, and you can ask your doctor for permission to try your thighs. Abdomen didn’t work well for me, but thigh and upper arm are both better.

Are your sensor reading accurate before these errors, or are you getting failed calibrations? Calibrating works best if you only do it 2-3 times in days 2-7, and only when the readings are steady. There are more advanced tricks we can discuss if your sensor is inaccurate.

I did call Medtronic they sent out a new order. I notice I have a lot of trouble with insterting it in the abdominal area. I think I’ll give my arm a try. Also, I notice sometimes when it fails there’s a lot of blood in the sensor. As for accuracy, its pretty accurate the first day but then if I’m like 75 it will say 60 and then it will keep dropping to below 40! I check my blood sugar on my meter and its no where near that.

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False lows are a bummer since they can impact insulin delivery. Hopefully moving the sensors to your arms will solve your issues. If not, there are more tricks to try.

Medtronic now has a new transmitter. Ask the rep how to get on the list for a new one. They are free. Rep told me Medtronic is offering it to address the problem you described. Happens a lot to me too. Sometimes if I sense it’s gojng to tell me to replace the sensor I will turn off the sensor feature on my pump for a few hours. Just be sure you’re bg is stable or check it regularly. You will still get alert in low It’s frustrating. I think it happens mostly when the sensor readings are way off from the actual numbers so it needs time to catch up.

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I had similar problems, as well as a high sensitivity to RF interference (iPad in lap, etc.), and many instances of pump requests for up to 7 BGs or calibrations a few minutes apart. The new transmitter (free from Medtronic) not only solved all those problems, but seems to have improved auto-mode control altogether. That’s definitely what you should request, IMO.

I have good results with sensor and infusion on opposite thighs, BTW. Abdomen is said to be the worst spot, but I don’t have enough real estate there, anyway.

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How long did You have to wait to get the new transmitter? Yes, it’s hard to find a good infusion site. My abdomen is worn out but the sensor falls out of other areas I’ve tried. Thigh is 50/50 so will have to try there more often.

Thank you! I will give Medtronic a call and order a new one.

Always call the 24 hour help line. Tell them what is happening and they will help you and replace the sensor no charge. I started the sensor 1 year ago and had issues many times. I only started wearing the pump August 2017. Was diagnosed late in life at age 55 with T1D and started with injectable pens. I kept telling Medtronic there needs to be more training on the pump AND sensor. I just kept calling. I was always kind and respectful to the 24 hour people, it’s not their fault and they were always so kind and helpful to me. Some nights I would not get much sleep being woke up every hour with an alert but still always ask them how they are doing and thank them using their name. That means a lot to people who are there to help. I am starting to feel much more confident using the sensor and soooo glad I hung in there. Also I pray A LOT. Hang in there. It gets better. Oh and btw, some of the issues were human error.

I got the new updated transmitter in early December after my old one failed. It worked well for about 4 weeks but I had a sensor fail at day 5 last week. It kept saying “sensor updating” and then would enter auto mode for maybe 30 minutes before repeating the cycle. During this time, my BG went to over 400! It finally failed. Last night While the pump was in my pocket, it vibrated and said “lost sensor signal, move pump closer to transmitter”. After searching for maybe 5 minutes, it did go back into auto mode. Seems to be working today but it’s only day 3. :blush:
Love auto mode when it works but am really disappointed in Medtronic for not solving all of these issues before going to market. I would not go with this company again☹️

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I waited 2 days for the replacement transmitter. It was probably quick because I called with (repeated) problems that they diagnosed as a result of the old transmitter. A key question they asked was the software version of the transmitter (under Status, Sensor).

What do you mean, “the sensor falls out”?

I’m a 10+ year Medtronic pump user. You’re right about Tech Support being a pain. First thing I say is I’ve used their pumps 10 years and my current pump 5 years. Yet they invariably read me thru the steps, using a pre-formatted problem solving software. Eventually, they say they will replace an item and send me a packet to mail in the old one. A little sensor comes in a BIG box, which goes into the high cost of their supplies. What makes me angry is the Dexcom 5g CGM lasts at least 14 days and is dead on accurate after the first day. Two years later Medtronic releases another dog of a CGM, and you’re stuck with it if you use the 670g in self-control mode.

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My 670g alarms every night. I get up to check only to find the sensor is inaccurate. It alarms when I am driving. Sort of distracting and dangerous. I have had consistent a1c of 7.8. Worst of my 25 years of being type 1. My diabetes team says I am doing great. Stable blood sugars. I absolutely would not recommend this pump. All that and I still use it in auto mode because It sort of does better then before. I dislike it, but blood sugar is very difficult to control. Hopefully something better comes along. Maybe Tslim or Dana . I am hopeful for better technology. I am disappointed with Medtronic.

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They told me to try my arm, too. I haven’t found any difference except for they fall out from your arm easier. They’re pretty bulky, you bump a wall or move your arm too much, and it’s out.
I had to get every piece replaced. I finally decided to stay in manual mode because in auto mode I couldn’t sleep for more than a couple hours without it going off about something.
Make sure you call every time it does that. They will replace the sensor as long as it happens in less than 5 days.

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I have using the pump 12 + years. I have tried the sensor, twice before the new one. Been through 4 or 5.
I have been using the libre system for maybe a year +.
I find it to work out just out fine. But Medtronic sent me another sensor, with the new pump. Told I would love it. Ok. I have been through about 13 sensor in 3 to 4 weeks. Only 1 worked like it should. All others failed. Warm up to first calibration. Then, waits and do another finger stick. Not excepted. Change sensor. I think I’m done with this. It’s a flawed system. They need to make these sensors like the libre system.
Easy to put on. And stays on. The 670 sensor, I had to pull the battery many, many times to reset it. Hours of time and stress.
I Hate the sensor. Medtronics get better. Or partner with libre and learn. No battery to charge. Done for 14 days.
Sorry I had to vent.
Thank You

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Sad reality of this company, as I researched them due to their poor quality yet lack of options from my insurer; the insurance for their own staff WILL NOT cover any product made by them. I guess their employee insurer knows better. Let that one sink in.

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Had the same problem as well. Same , same. Received a new sensor and all is working well, so far. My second week and no problems with the new one.

After fighting with Medtronic sensor issues myself and spending hours on the phone with support personnel, I have learned a couple issues that the medtronic sensor can’t cope with. DEHYDRATION is a major problem for the sensor. Not using their adhesive patches gave me fits, I sweat excessively in the summer and tried several different tapes and they all messed with the sensor. I also have been pumping for 16 years and when the sensor gets dumb during sleep time I shut it off and rely on my preset nasal rates. Also I don’t calibrate when below 90 or above 170. I learned that the sensor updating error is often result of rapid drops or rises in bg. Never try to calibrate when this situation is happening as the interstitial fluid just doesn’t react as fast as blood does and it creates an internal error. I was quite unhappy with the system when i first started using it in summer of 2017 but now I had the best A1c I have had in last 10 yrs of 6.4 last month . I will admit it is not a simple solution but I am pleased with the end results for me.

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I’ve had so many issues trying to insert my cgm and getting it to connect so I never put the second tape on it until I know for sure that it works so that way I can take it off and try it again instead of having to take the whole thing off and inserting a new one . My issue is that I always hit a vein and I bleed so much that I have to put a new one on