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Using Dexcom ONE in the Long Run

Why isn't my transmitter working, and/or why is my Dexcom CGM System telling me to pair a new transmitter?

Last Updated · November 3, 2022

Dexcom ONE transmitters last up to 90 days from activation. You can find your transmitter’s Activated On date by going to Settings > Transmitter in the Dexcom ONE app.

Also, be aware that a transmitter must be activated within 5 months of its shipping date to function.

If your transmitter is more than 90 days old and not working, you must use a new transmitter. You will not be able to start a sensor session past day 90. To avoid any unnecessary issues with your Dexcom CGM System, contact your supplier to have a new transmitter in hand by day 90.

If your transmitter is less than 90 days from activation, contact technical support for troubleshooting at

5-step learning journey

Discover education resources, organised in a 5-step journey, to learn key information about your Dexcom ONE CGM system, from getting started, your first 10 days, to using Dexcom ONE in the long run.

Step 1: The basics of CGM
Step 2: Getting started
Step 3: Your first 10 days
Step 4: Using Dexcom ONE in the long run
Step 5: Understand your Diabetes trends