What happens if Key Battery dies?

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

Gangeroo | November 10, 2012

How do you change the battery in the keyfob?

Teoatawki | November 10, 2012

The underside of the nose of the fob pops off with a fingernail, exposing the CR2032 3V battery, (Same as on the motherboard of most PCs).

bpmeier | January 20, 2013

so this is actually happening to me now. dropped friends off at the train station and when i got back inside, the display says, "key not inside. car won't start.". have swapped fob batteries but no luck. tesla engineering on the line but no solution yet. kind of a nightmare scenario. sunday so local service not open. car wont move & im in a tow-zone.

drp | January 20, 2013

It's listed in e manual

nickjhowe | January 20, 2013

@BrianP - If the car will open but not start, make sure you put the key in the cupholder. That's where the RFID receiver is.

Getting Amped Again | January 20, 2013

I'm copying this post of mine from another thread. It's my campaign to get rid of the fob (or at least give us the option of going fob-less).

The solution for this is to have the functions of the fob built into the mobile app. Require a 4-digit PIN to access the app (or just use the phone security) and and you have a more convenient and more secure fob replacement. Program in all the fob features that people want, like driver profiles, all windows down, go to and display home page, media start, etc.

Surely someone can figure out how to handle the proximity features of the fob via software (GPS?). If TM can unlock your car remotely then they (and us) should be able to do everything else remotely. I have an app that controls my cable box, why can't I have an app that controls my S? It's all talking to a computer through a network.

Keep the fobs home for emergencies (but if you're over 25 how often do you lose your phone?)

ir | January 20, 2013

@Getting Amped Soon: No need to use GPS to prove proximity to the car. Just use Bluetooth, it already uses cryptographic strong communication. There are garage openers that use the same trick to know when to open.

Amped | January 21, 2013

The manuals,

Extra fob is $249

harvey | January 31, 2013

@Getting Amped Soon
Great ideas. Would love to see them implemented!

Tâm | February 2, 2013

You can now access to your car (among other things) with your phone app:

Lock / Unlock / Honk Horn / Flash Lights / Vent Roof.

JoeFee | February 3, 2013

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.

Tâm | February 3, 2013


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.

July10Models | February 3, 2013

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

suegie | February 3, 2013

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.

larryh | July 13, 2013

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.)

Tâm | July 13, 2013


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...)

Rocky_H | January 9, 2014

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.

Sudre_ | January 9, 2014

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

inside the car:

Outside the car:

I'd say that's pretty consolidated.

Keith72 | January 9, 2014

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.

akikiki | January 9, 2014

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.

Rocky_H | January 10, 2014

@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.

jerryortiz11 | December 2, 2015

There is a mechanical key within the Smart Key that will open the driver's door. Once you enter the vehicle, hold the Smart Key next to the START button and depress. This will most likely allow the engine to start. If the engine doesn't start and the power door locks are inoperable, the concern may be a weak engine battery and not a weak Smart Key battery...

Rocky_H | December 2, 2015

@jerryortiz11, What in the world car forum do you think you are on? This is the forum for Tesla Motors. The key fobs for Tesla cars do not have a mechanical key in them, and there is no START button.