Diabetes educator CATE MITCHELL shares 7 quick troubleshooting tips if your CGM (continuous glucose monitor) doesn’t seem to be working properly.
1. First, check the basics
Sensor placement: Is the sensor inserted correctly and not loose or peeling off the skin?
Transmitter connection: If your CGM uses a separate transmitter (Dexcom G6, G7), check that it’s connected securely.
Phone or receiver: Check Bluetooth is on, the app is open, and your phone is within range (usually 1.5 metres.)
Battery level: Ensure your phone, receiver and transmitter (if rechargeable) have power.
Compatibility: Check that the mobile app is the correct version for Australia, and your phone OS (operating system) is compatible. If you have a new phone or smartwatch, you can check compatibility on the manufacturer’s website.
Updates: Check that both your phone and CGM app are updated.
2. Try restarting and reconnecting
Close and reopen the CGM app.
Toggle Bluetooth off and on.
If needed, restart your phone or receiver.
If using Abbott Freestyle Libre 2+, try rescanning the sensor to your phone.
3. Check if it’s just a temporary signal loss
Signal gaps are common if you’ve been moving around, showering or sleeping on the sensor. If possible, avoid lying on the sensor when sleeping.
Wait about 10–15 minutes — the signal often comes back automatically.
4. Do a blood glucose finger prick check
If readings are missing or the numbers don’t seem to match the signs and symptoms you are experiencing, always verify with a finger prick check before making any insulin or food decisions.
5. Inspect for sensor issues
If the sensor is painful, loose or causing bleeding, it may not work correctly, and you might need to replace it.
Check for skin irritation or infection at the site.
6. Contact customer support
Most CGM companies will replace a faulty sensor or transmitter for free if it fails early.
Keep the failed sensor in case it needs to be returned and have the following information ready when you call or chat with support:
Sensor serial number
Date/time of issue
Error message (if any)
Contacts
Libre (Abbott): 1800 801 478 (24-hour product helpline)
Medtronic Guardian: 1800 777 808 (24-hour product helpline)
Dexcom: 1300 851 056 (technical support open Monday to Friday 7am to 9pm AEST; Saturday 9am to 6pm)
7. Call the Diabetes WA Helpline or come to our clinic
CGMs provide a lot of information, which is helpful for diabetes management but can be a little overwhelming. We answer a lot of questions on the helpline about diabetes technology, and we are always happy to help you get started on new technology, including CGMs, or troubleshoot.
Call us for free on 1300 001 880.
An appointment with a diabetes educator can help you learn to use your CGM to support you and your lifestyle.
Get in touch if you’d like to make an appointment at our clinic, or make a Telehealth appointment if you’re living in rural or remote Western Australia.
