Under normal use, the accessory key fob has a battery that lasts for up to one year, depending on key fob version and selected vehicle settings. When the battery is low, a message displays on the touchscreen.

To replace the key fob battery:

1. With the key fob placed button side down on a soft surface, release the bottom cover, using a small flat-bladed tool.
2. Remove the battery by lifting it away from the retaining clips.
3. While avoiding touching the battery's flat surfaces, insert the new battery (type CR2032 ) with the ‘+’ side facing up.
   Note

   Wipe the battery clean before fitting and avoid touching the battery's flat surfaces. Finger marks on the flat surfaces of the battery can reduce battery life.
   Note

   CR2032 batteries can be purchased from any retailer that sells batteries.
4. Holding the bottom cover at an angle, align the tabs on the cover with the corresponding slots on the key fob, then press the cover firmly onto the key fob until it snaps into place.
5. Test that the key fob works by unlocking and locking Model 3.