In Tesla’s Model 3 (2024+) and Model Y (2025+) owner’s manuals for North America, the key fob is an accessory that runs on a CR2032 coin cell.
The battery it takes
Tesla’s Model 3 and Model Y owner’s manuals for North America give a CR2032 for the accessory key fob, fitted with the + side facing up.
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How to change it, in Tesla’s steps
- Place the key fob button side down on a soft surface and release the bottom cover with a small flat-bladed tool.
- Lift the old battery away from the retaining clips.
- Fit the new battery + side up, without touching its flat surfaces.
- Hold the bottom cover at an angle, line its tabs up with the slots on the fob and press it on firmly until it snaps into place.
- Lock and unlock the car to check the fob works.
Wipe the battery clean before fitting it. Tesla says finger marks on its flat surfaces can reduce battery life.
How long it lasts
Under normal use, the fob’s battery lasts up to one year, depending on the key fob version and the car’s settings. A message on the touchscreen says when it’s low.
If the key fob or phone key is dead
A key fob with a dead battery can still drive the car: scan it on the card reader on the driver’s side door pillar, as you would a key card. If your phone key’s battery is dead, Tesla says to use the key card to unlock, drive and lock the car.
The card reader sits about a third of the way up the driver’s side door pillar. Once inside, press the brake pedal within two minutes of scanning the key card to power up. After two minutes, place the card near the reader in the wireless phone charger on the center console to start the two minutes again.
Keep coin batteries away from children
Tesla warns that a swallowed coin cell can cause severe internal burns within two hours and can lead to death. Keep new and used batteries away from children, and if the battery compartment doesn’t close securely, stop using the fob and keep it away from children.
The National Capital Poison Center says that if anyone swallows a battery, immediately call the 24-hour National Battery Ingestion Hotline at 1-800-498-8666 or your poison center at 1-800-222-1222. Don’t delay. Immediate treatment decreases severity.