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What happens if Key Battery dies?

Given that the Model S operates automatically off of the Key Battery, what will a driver do if the Key Battery dies. This happened to me once with a Lexus key fob. The battery died and I could not operate the car until I had replaced the battery. But what if you are out on a camping trip or someplace else remote where a replacement battery is unavailable. Is there a backup battery in the key fob? Is there someway to enter an "unlock" code into the car so you can start it? How do you open a door if the key battery dies?

Tesla may already have published the answers to these questions. If so, I would appreciate any links to pages that discuss this topic.

Thanks for your help

I just got an error on the tough screen noting the fob battery is low…so you will have a warning before the battery goes dead. I’ve had the car since Nov 2012 but have only have 700mi on it so I’m surprised the battery is shot already.


Thanks for the warning!

November, December, January: Yikes! That's only 3 months. I am on month number 2, I'd better get another battery for my fob soon.

They are pretty cheap. 5 batteries / 0.34 + 1.65 shipping = $1.99 / 5 = $0.40 each.

Those are the same batteries my dog collar uses. There will always be a spare near by.

Both of my batteries are dying, and I only got the car Thanksgiving weekend. Thanks for posting the image reminded me I need to take care of this immediately! I got the error on my screen as well.

The manual says:
If the vehicle doesn’t unlock
when you walk up to it, or
when you press the unlock
button on your key, it is
possible that the key’s battery
is dead. If this is the case, you
can unlock the passenger door
by positioning the key near
the base of the passenger
side windshield wiper, as
shown. Then press the front
passenger door handle to open
Model S.

I tried this with my spare key with the battery removed and could not get it to work.

Is there some trick to this?

Similary, the key with no battery was not detected in either cup-holder.

Perhaps there is a difference between no battery and a dead battery?

(Yes, I verified that the key works with the battery.)


Dead-battery FOB usage is not useable at current with Model S (although Dead-battery FOB usage works flawlessly with other car companies)

I would classify this feature as "to be fulfilled" (same as 4G LTE already built-in, WIFI at anytime now...)

I have now seen three locations listed inside the car for where to put a dead fob for driving it--cupholder, under front of driver's seat, and against the dash just under the 12V accessory outlet. And for unlocking, I've seen two locations listed--at the base of the right windshield wiper and at the back of the right front wheel well. It sure would be nice if there was some better consolidated information.

Rocky, you could try the owners manual....

inside the car:

Outside the car:

I'd say that's pretty consolidated.

When the battery in my fob started to get low, I got a warning indicating low key battery on both the 17" screen and the driver's screen. I contacted Tesla and they ran diagnostics remotely, then had two new batteries delivered to me within 3 days via snail mail. I received an email and phone call after the diagnostics were run (the same day I notified them). My fob was still working when the new batteries arrived, but I carried the spare fob with me just in case.
I've had my car since March 2013 with about 5000 miles on it.

Several folks have put a spare fob battery taped both to a place on the inside and the outside of the car, in case its needed if the fob fails. Don't forget to include a small screwdriver or flatten nail to help pop the cover off and the batter out of the fob.

@Sudre_ See? You just proved my point. I just went through the owner's manual PDF you linked to, and it shows the base of the windshield wiper location for unlocking. But on the Tesla owners club forums, someone has uploaded a series of photos showing the owner's manual displaying on the touchscreen in their car, and it shows the back of the wheel well instead. So two different copies of the owner's manual show it in two different places. That's fabulous. Maybe they changed it at some point, but I wonder when and which cars have it in which location.

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