Dexcom G7/G6 Sensor Not Reading — No Signal Fix

Hello. If your Dexcom G7 or G6 CGM is not showing readings or is displaying a signal loss or sensor error, this guide walks through the most common causes and how to fix them. Step 1: Understand the error message. The Dexcom G7 and G6 show different alerts. A "Signal Loss" alert means the sensor is working but has temporarily lost connection to your receiver or phone. A "Sensor Error" or "?" on the screen means the sensor itself may be malfunctioning. A "No Readings" message usually means the sensor is in its warm-up period or has expired. Step 2: Wait for the warm-up to complete. The Dexcom G7 has a 30-minute warm-up after insertion. The Dexcom G6 has a 2-hour warm-up. During this time, no glucose readings will display. This is normal — do not try to calibrate or restart the session during the warm-up period. Step 3: For signal loss — move your receiver or phone closer. Dexcom Bluetooth range is typically 20 feet. Walls, furniture, and other devices can interfere with the signal. Keep your receiver or phone within 10 feet of the sensor for reliable readings. Step 4: Restart Bluetooth on your phone. Open your phone Settings, turn Bluetooth off, wait 10 seconds, and turn it back on. Then check if the Dexcom G7 app reconnects automatically. If it does not reconnect, open the Dexcom app and wait up to 5 minutes. Step 5: For sensor errors on the G7 — wait up to 3 hours. The G7 sensor sometimes shows a temporary error while calibrating its readings in the first 24 hours. If the error clears on its own within 3 hours, the sensor is working correctly. Step 6: For sensor errors on the G6 — check the transmitter connection. Remove the transmitter from the G6 sensor by pressing the latch with a coin and sliding it out. Reinsert the transmitter firmly until you feel a click. A loose transmitter is one of the most common causes of G6 signal loss. Step 7: If errors persist beyond 3 hours — contact Dexcom for a replacement. Dexcom has a sensor replacement policy. Call 1-888-738-3646 or use the Dexcom app to report a failed sensor. Have the sensor lot number ready — it is printed on the sensor packaging. Replacements are typically shipped free of charge. Step 8: When to use a fingerstick. During any signal loss or sensor error period, check your blood glucose with a fingerstick meter for treatment decisions. Do not rely on sensor readings when they are flagged as uncertain. Still need help? Find a CGM provider near you →