Transmitter Not Pairing
Dexcom Continuous Glucose Monitor
Severity: CriticalWhat Does This Error Mean?
Dexcom transmitter not pairing is most often caused by the transmitter still being linked to a previous session, the phone Bluetooth cache needing a clear, or the phone being too far from the transmitter during pairing. Force-stop the Dexcom app, clear Bluetooth cache on Android, and retry within 6 inches of the transmitter.
Affected Models
- Dexcom G6
- Dexcom G7
- Dexcom ONE
Common Causes
- Transmitter still linked to a previous session — not properly stopped in the app
- Bluetooth cache on Android causing the phone to try to connect to the old transmitter session
- Phone too far from the sensor during initial pairing
- Dexcom app not updated to the latest version
- Another device (old phone, receiver) paired to the same transmitter taking priority
How to Fix It
-
Stop the current sensor session before pairing a new transmitter.
In the Dexcom app, go to Settings > Stop Sensor. A transmitter cannot pair to a new session until the previous session is explicitly stopped. If you are setting up a completely new sensor and transmitter, confirm the previous session was stopped.
-
Force-stop the Dexcom app and reopen it.
On iPhone: swipe the Dexcom app up from the app switcher to close it. On Android: go to Settings > Apps > Dexcom > Force Stop. Reopen the app and try pairing again. A cached app state can prevent the pairing handshake from completing.
-
Clear Bluetooth cache on Android.
Go to Settings > Apps > Bluetooth > Storage > Clear Cache. This step is Android-only and does not apply to iPhone. An outdated Bluetooth cache on Android sometimes prevents Dexcom transmitters from being discovered or paired correctly.
-
Keep the phone within 6 inches of the sensor during pairing.
Dexcom transmitters have a limited range during the initial pairing handshake. Hold the phone directly over the sensor site or place it touching the sensor location. Once paired and the warm-up period completes, normal range (up to 20 feet) is restored.
-
Unpair from any other devices.
Dexcom G6 can be paired to a maximum of 2 devices simultaneously. If two devices are already paired (e.g. your phone and a Dexcom receiver), you cannot add a third. Remove the transmitter from one device before pairing to a new one.
Frequently Asked Questions
How do I know if my Dexcom transmitter is compatible with the G6 app?
Dexcom G6 transmitters have a serial number starting with 80 or 81. Transmitters starting with 8G or 8H are G7 transmitters and will not work with the G6 app. Check the transmitter serial number against the sensor box to confirm compatibility.
My Dexcom G7 does not need a separate transmitter — why is pairing failing?
The Dexcom G7 has the transmitter built into the sensor pod — there is no separate pairing step for the transmitter. If the G7 is not pairing, the issue is the sensor session start in the app, not a separate transmitter. Follow the app's in-app instructions to scan the sensor and start a new session.