Freestyle Libre Error Codes English

Freestyle Libre 1, 2, and 3 Error Codes updated 01.08.24:

Libre 1:

    373: Sensor error - Glucose reading is unavailable. Try scanning again in 10 minutes.

Libre 2:

    335: Scanning error - The smartphone failed to scan the sensor. Scan the sensor again. Make sure to hold the back of the smartphone close to the sensor. When you hear the first tone or vibration, hold the smartphone still until you hear the second tone or vibration.
    338: The sensor is starting up. This sensor has been started but is not yet ready for use.
    365: Your sensor is not working. Please remove the sensor and start a new one.
    366: Check the sensor. Please check your sensor. If it is loose from the skin, please remove the sensor and start a new one. If it is properly applied, try restarting the sensor.
    373: Sensor error - Glucose reading is unavailable. Try scanning again in 10 minutes.
    380: The sensor is having trouble measuring glucose levels. Please restart the sensor or switch to a new sensor if the problem persists.

Libre 3:

    57: You have applied a new sensor/it is starting up.
    365: Your sensor is not working. Please remove the sensor and start a new one.
    366: Check the sensor. Please check your sensor. If it is loose from the skin, please remove the sensor and start a new one. If it is properly applied, try restarting the sensor.
    373,P: Glucose reading is unavailable. Try scanning again in 10 minutes.
    373,E, 373,F, 373,I: Possibly related to changes in blood sugar levels.
    380: The sensor is having trouble measuring glucose levels. Please restart the sensor or switch to a new sensor if the problem persists.

Codes in the 4000-4999 series are general error codes. Some observed codes include:
4005, 4008, 4010, 4011, 4013, 4202, 4193, 4224, 4225, 4227

General Error Codes for Both Libre 2 and 3:

    410: This code indicates an error during the sensor's initialization.
    411: This code indicates a problem with the sensor insertion process.
    412: This code indicates a problem with the communication between the reader and the sensor.
    4123: This code indicates a problem with the sensor's communication or signal.
    413: This error usually occurs when the sensor has expired or has reached its maximum usage time.
    414: This code indicates a problem with the sensor's signal strength.
    415: This error usually occurs when the sensor has failed or is not functioning properly.
    416: This code indicates a problem with the sensor temperature.
    417: This code indicates an error during the sensor insertion process.
    418: This code indicates an error during the sensor warm-up process.
    419: This error usually indicates a problem with the sensor signal.
    420: This error usually occurs when the glucose reading is too high.
    421: This error usually occurs when the glucose reading is too high or exceeds the maximum limit.
    422: This code appears when the glucose reading is too low or falls below the minimum limit.
    4222: This error usually occurs when there is a discrepancy between the sensor and blood glucose levels.
    423: This code appears when the glucose reading is too low.
    426: This code appears when the glucose reading is not available.
    431: This code appears when the sensor's glucose readings are significantly different from expected values.
    434: This error indicates a problem with the sensor's signal or data transmission.
    435: This error indicates that the glucose reading is unreliable or inaccurate.
    436: This error indicates a problem with the sensor temperature.
    430: This error indicates that the sensor is expired or near its expiration date.
    440: This error indicates a problematic or poor sensor start-up process.
    445: This error occurs when the sensor cannot read glucose values due to a sensor-related error.
    450: This code indicates an error during the sensor initialization process.
    455: This error occurs when the sensor detects erroneous or inconsistent glucose readings.
    460: This code indicates an error during communication between the sensor and the reader.
    465: This error occurs when there is a problem with the sensor calibration.
    470: This code indicates an error during the sensor warm-up process.
    475: This error occurs when the sensor detects erroneous or inconsistent glucose readings.
    480: This code indicates a general sensor error that cannot be identified more specifically.
    485: This error occurs when there is a problem with the sensor unit or sensor communication.
    490: This error occurs when the sensor detects an error or abnormality in the measurements.
    495: This code indicates an error during the sensor start-up or initialization.
    500: This error occurs when there is a general error in the sensor unit.
    505: This code indicates an error in the sensor algorithm or data programming.
    510: This error occurs when there is a problem with the sensor's electrical connection or power supply.
    515: This code indicates an error during the sensor calibration process.
    520: This error occurs when there is an error or misalignment in the sensor measurements.
    525: This code indicates an error during the sensor update process.
    530: This error occurs when there is a problem with the sensor's memory or data storage.
    535: This code indicates an error in the sensor temperature compensation.
    540: This error occurs when there is a problem with the sensor's response or response time.
    545: This code indicates an error during the sensor recognition process.
    550: This error occurs when there is a general error in the sensor operation.
    555: This code indicates an error in the sensor's alarms or alerts.
    560: This error occurs when the sensor experiences interference from external sources.
    565: This code indicates an error during the sensor measurement process.
    570: This error occurs when there is an error in the sensor calibration algorithm.
    575: This code indicates an error in the sensor signal quality.
    580: This error occurs when the sensor detects deviations or inconsistencies in the measurements over time.
    585: This error occurs when there is an error in the sensor signal filtering or sudden changes in signal strength.
    590: This code indicates an error during the sensor battery voltage monitoring.
    595: This error occurs when the sensor detects an error or inconsistency in the algorithm for data analysis and calculations.
    600: This code indicates a general error in the reader unit.
    605: This error occurs when the reader unit fails to communicate with the sensor unit.
    610: This code indicates an error in the reader calibration process.
    615: This error occurs when the reader unit cannot process or interpret the sensor data correctly.
    620: This code indicates an error during the reader start-up or initialization.
    625: This error occurs when there are problems with the reader display or display functionality.
    630: This error occurs when there is a problem with the reader battery voltage or power supply.
    635: This code indicates an error during the reader data transfer process.
    640: This error occurs when the reader unit cannot establish a connection to the sensor unit.
    645: This code indicates an error in the reader temperature compensation.
    650: This error occurs when the reader unit detects an invalid or unreadable sensor.
    655: This code indicates an error during the reader alarms or alerts.
    660: This error occurs when the reader unit cannot process or interpret the sensor signals correctly.
    665: This code indicates an error in the reader signal processing or filtering.
    670: This error occurs when there is an error or misalignment in the reader measurements.
    675: This code indicates an error in the reader calibration algorithm.
    680: This error occurs when the reader unit detects an error during the sensor warm-up process.
    685: This code indicates an error in the reader algorithm for glucose calculation.
    690: This error occurs when there is a problem with the reader data storage or memory.
    695: This code indicates an error during the reader update process.
    700: This error occurs when the reader unit cannot establish a connection to the sensor unit due to signal problems.
    705: This code indicates an error during the reader sensor detection process.
    710: This error occurs when there is an error during the reader battery voltage monitoring.
    715: This code indicates an error in the reader response or response time.
    720: This error occurs when the reader unit experiences software or system problems.
    725: This code indicates an error during the reader calibration process.