A Signal Loss warning may indicate a phone connection or software problem rather than a failed sensor, Abbott says, with users advised to check settings and use a backup glucose meter.
Abbott says users of the FreeStyle Libre 3 Plus system who see a “Signal Loss” alert after updating the app should not assume the sensor has failed. The company’s support guidance says the warning usually means the phone and sensor have stopped communicating, often because the handset has moved out of range, Bluetooth has been switched off, or the app is no longer allowed to run properly in the background. A report from Diabetech also said some users experienced extended signal loss after a recent security update, suggesting that in at least some cases the issue may have been triggered by software rather than the sensor itself.
Abbott’s official advice is to start by putting the phone back within about 33 feet of the sensor and waiting two to four minutes for the connection to recover. If that does not work, the company recommends toggling Bluetooth off and on again or restarting the phone. Abbott also says the Libre app should not be force-closed, because that can interrupt data flow and delay recovery. If the signal does not return, the company advises users to contact customer care rather than immediately replacing the sensor.
The company’s guidance also points to settings that can change after an operating system or app update. On Android, users may need to check Bluetooth and Nearby Devices permissions, as well as battery restrictions that can prevent the app from running in the background. On iPhone, Bluetooth access and notifications should be enabled, and the app should be left open to continue receiving readings. The practical point, Abbott says, is that a CGM sensor can be working normally while the phone has simply stopped listening for its data.
Abbott says a Signal Loss warning is not the same as a Sensor Error. The company’s FAQ on the signal-loss alarm explains that the alert is triggered after 20 minutes without communication, while signal loss itself can begin after about five minutes. It also notes that the FreeStyle Libre 3 Plus is designed to work at up to 33 feet under ideal conditions, although walls and other obstructions can shorten that range. If the app later shows a Sensor Error or the sensor reaches the end of its 15-day wear period, users should follow the on-screen instructions and seek support if the problem continues.
For people relying on the sensor for diabetes management, Abbott stresses that a backup blood glucose meter should be used whenever readings are unavailable or do not match symptoms. That warning is particularly important for anyone using the sensor with an automated insulin delivery system, where a communication failure can affect treatment decisions. While the company says many signal-loss problems can be fixed with simple phone settings, it also advises users to seek help promptly if the connection does not return.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
