Under normal use, the 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 flatbladed 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 CR2330) with the ‘+’ side facing up.
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 S.