My M400 is not charging

Make sure that M400 charging area is dry

Open the USB port cover and rinse the USB port with lukewarm water after each training session. After rinsing, leave the cover open for a while to let the USB port dry. Do not charge the device when the USB port is wet.

Check that M400 charging area is clean

M400 charging area

If your M400 doesn’t charge properly, or if it doesn’t connect to FlowSync, it could be because the charging area on the back of the product is not clean enough. Gently wipe off any dirt. Don't use any sharp tools for cleaning to avoid scratching.

Do NOT use alcohol, cleaning chemicals, or any abrasive material such as steel wool.

Check that the USB cable works.

  • Make sure the USB connector is firmly in place.
  • Remove and replug the USB cable into your Polar M400.
  • If your Polar M400 plugged into your computer via USB Hub, try plugging it in directly to the computer's own USB port.
  • Try the other USB port(s).

If the cable that came with M400 doesn't seem to work, try with another USB cable that has worked to transfer data to your computer from another device (e.g. camera).

If the above doesn't help, please contact your local Polar service for further assistance.

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