The short answer
- Get in first. On a Model 3 or Model Y, tap a key card against the reader on the driver’s side door pillar. Tesla’s manual says the card is there for exactly this: “In situations where your phone key has a dead battery, or is lost or stolen, use your key card to unlock, drive, and lock Model 3.” No card on you? If the phone still has signal, Tesla says “you can still access the vehicle by manually unlocking and starting the vehicle with the Tesla app.”
- Then check seven things. Tesla’s support page lists them: no third-party Tesla apps on the phone, location permission set to “Always Allow,” airplane and power-saving modes off, the latest Tesla app, signed in to the right Tesla Account, Bluetooth on, and Allow Mobile Access enabled on the car’s touchscreen.
- If that fails, reset the phone key from the Tesla app: “Tap ‘Security & Drivers’ > ‘Phone Key Best Practices’ > ‘Reset Phone Key.’”
One thing to know before you start. The phone key runs on Bluetooth Low Energy (BLE), a low-power form of Bluetooth that the car uses for a different job than music and calls. Tesla’s service guide puts it in one line: “BLE is used for passive functions like phone key.” So a phone that is happily playing music through the car can still fail as a key.
A note on scope: the manual quotes below come from Tesla’s two Model 3 manuals, and the service guide is the same for the Model 3 and Model Y. The Model S, Model X and Cybertruck put the inside reader in a different place, covered in the key card section, and the oldest Model S and Model X cars have no phone key at all.
Find your symptom
| What you see | Most likely cause | What to do |
|---|---|---|
| Doors do not unlock as you walk up | Phone Bluetooth off, battery low, or power-saving mode on | Tap the key card on the door pillar, then run the seven-point checklist below |
| App shows the phone key as disconnected | Signed out of the app, app not running in the background, or location not set to Always | Sign in, reopen the app, fix the permission |
| Doors unlock but the car will not shift into Drive | Tesla gives a fix for this one, not a cause | In the app, tap Controls, then Start, and press the brake |
| Only the driver’s door unlocks | Driver Door Unlock Mode is on | Controls > Locks, turn it off |
| Car does not lock when you walk away | Any of seven conditions Tesla lists, such as a door ajar or a key left inside | See the Walk-Away Door Lock section |
| Key card does nothing | Card not held long enough, wrong spot, or not paired to this car | Hold it on the pillar reader for one or two seconds; pair a new card first (see the key card section) |
| Key fob does nothing | Dead coin battery or radio interference | Scan the fob on the door pillar like a card; replace the CR2032 |
| You lost every key card and fob | Nothing is broken, but the car needs one paired | The owner can pair a new card from the Tesla app with no working key; see the replacement section |
| Nothing works, and the car shows no sign of life | Not a key problem | See “When no key works at all” below |
How to get into your Tesla right now
With a key card. On 2017 to 2023 Model 3s the manual says to tap the card “against the card reader located just below the Self-Driving camera on the driver’s side door pillar.” The manual for the current Model 3 describes the same reader as “approximately one third the way up of the driver’s side door pillar.” Both editions add the detail most people miss: “you may need to hold it against the transmitter for one or two seconds.” A quick wave does not count. Use the driver’s side; Tesla’s shop listing for the card says “access cannot be granted from the passenger side of the vehicle.”
Then start it within two minutes. Once inside, the manual says to “power up Model 3 by pressing the brake pedal within two minutes of scanning the key card.” Miss that window and you scan again inside the car. On 2017 to 2023 cars that reader is “behind the cup holders on the center console”; on the current Model 3 it is “in the wireless phone charger on the center console.” This site’s reference car, a 2019 Model 3, is a behind-the-cup-holders car.
With the app. If the phone has a data connection but the Bluetooth key has dropped, unlock from the app and use its Start control. Tesla’s steps for a car that will not shift into Drive are the same ones: “Open the Tesla app. Tap the ‘Controls’ tab. Tap ‘Start.’ While pressing the brake pedal, confirm whether the vehicle can shift into Drive.” Unlike the Bluetooth key, this route goes through the app, so the phone needs a working data connection.
With a key fob whose battery died. The manual covers it: “you can still use it to drive the vehicle by scanning the key fob on the card reader located on the driver’s side door pillar (like the key card).”
Tesla’s own phone key checklist
Tesla publishes two lists. The support page’s version, in Tesla’s words: “If your phone key is not working as expected, confirm the following”:
- “You have no third-party Tesla vehicle apps on your phone.”
- “Location Permission for the Tesla app is set to ‘Always Allow.’”
- “Airplane and power-saving modes are both turned off.”
- “You have the latest version of the Tesla app.”
- “You are signed in using your Tesla Account and you are the owner or driver of that vehicle.”
- “Your phone’s Bluetooth is turned on.”
- “You’ve enabled Allow Mobile Access on the vehicle touchscreen by tapping ‘Controls’ > ‘Safety’ > ‘Allow Mobile Access.’”
Tesla’s service guide for the Model 3 and Model Y adds the items that list leaves out. On the phone: “Charge your phone; if your phone battery is too low, it may not support Bluetooth functions,” update the phone’s own software, and “turn your phone off and on again.” In the app: “Verify you’re logged into the Tesla mobile app while using your phone key” and “ensure the Tesla app is running in the background.” On the car: “If the vehicle Battery is too low, you may lose Bluetooth function,” keep the car’s software current under Controls > Software, and restart the touchscreen. The Model Y page reads the same. The frozen or black screen guide has the restart steps.
Tesla adds one habit that costs nothing: “For optimal performance, hold your phone in your hand as you approach or leave the vehicle. Some clothing or bags can interrupt or block your Bluetooth connection.”
Why does the Tesla phone key say disconnected?
Tesla’s service guide says that “due to several potential factors, Bluetooth or BLE may sometimes disconnect or experience issues in the pairing process.” A disconnected phone key is that situation: the link between this phone and this car is down. Tesla’s lists point to these causes.
The phone shut Bluetooth down to save power. The manual warns that “many phones disable Bluetooth when the battery is low.” Power-saving mode is on Tesla’s checklist for the same reason. This is the cold-morning failure: a phone at a few percent, in a pocket, in low-power mode.
The app was closed or signed out. The manual is blunt: “You must remain logged in to your Tesla account to use your phone to access Model 3.” If the app has signed you out, the key stops working until you sign back in.
Location permission changed. Tesla wants it on “Always Allow,” and the manual’s setup steps say to select “Location > Always.” If that permission has been changed to anything else, set it back.
Too many phones. The manual says “Model 3 can connect to three phone keys simultaneously,” and if more are detected you need to “move the other connected phone key(s) out of range or turn off its Bluetooth setting.” A household with four paired phones in one driveway can hit this.
One thing that is not the cause: a lost internet connection. “Once a phone has been authenticated, it no longer requires an internet connection to be used as a phone key for Model 3.” The key works in a garage with no signal. The app’s remote unlock does not.
Phone key connected but not working
Start with the settings Tesla’s support page points to.
If the doors open but the car will not go into Drive, Tesla’s fix is the app’s Start control, described above. If only the driver’s door opens, Tesla says “you most likely have Driver Door Unlock Mode enabled,” and the switch is under Controls > Locks.
If the app has no Controls tab at all, the phone key was never finished: “You will not see the Controls tab if a phone key has not been set up.”
How to reset a Tesla phone key
Tesla documents a reset from the app and a removal from the car’s touchscreen. Try the app first.
From the app: “Open the Tesla app. Tap ‘Security & Drivers’ > ‘Phone Key Best Practices’ > ‘Reset Phone Key.’” Tesla’s last-resort sequence, if a specific fix did not work, is three steps: “Turn Airplane Mode On, then Off in your mobile device’s settings. Restart your vehicle’s touchscreen. Reset your phone key in the Tesla app.” After that it says to “contact the Customer Support team.”
From the car: the service guide says that for BLE phone key issues, “when in the vehicle, navigate to Controls > Locks and remove your phone as ‘Phone as Key’. Then set it back up again.” It attaches a warning twice, and it is worth obeying: “only do this while you are in the vehicle and have a reliable back up key available (such as a key card),” and “do not unpair your vehicle to your phone or remove it as phone key without a working key card nearby.” Delete the phone key in a parking lot with no card in your wallet and you have locked yourself out by hand.
If setup itself fails, Tesla’s advice is short: confirm mobile access is enabled and that you are inside the car, then “turn the Bluetooth on your phone off and on” and “pair your phone as a key.” If the automatic setup does not complete, “you may be too far away from your vehicle,” and the app will walk you through finishing it with the key card.
Tesla key card not working
A key card is not like the fob: the manual describes it as using “short range radio-frequency identification (RFID) signals,” and the only battery instructions in the Keys chapter are for the key fob. Tesla’s pages point to four things to check when a card fails.
It was not held still. Hold it against the reader “for one or two seconds,” and the manual notes “you may need to physically touch” the pillar with it.
It is the wrong spot. The pillar reader is on the driver’s side only. Inside, the reader is behind the cup holders on older Model 3s and in the wireless phone charger on the current car. For the Model S, Model X and Cybertruck, Tesla’s pairing steps say to “place the key card at the top of the left phone charger against the center divider, point the front of the card down and swipe downwards.”
The two minutes ran out. The card unlocked the door, you loaded the trunk, and now the car will not start. Scan again on the inside reader and “your two minute authentication period restarts.”
It was never paired to this car. A new or replacement card does nothing until it is added under Controls > Locks > Keys > Add Key, and the last step is to “scan a key card or key fob that has already been paired to the vehicle to confirm new key pairing.”
A card also will not lock the car for you. “When you walk away carrying your key card, Model 3 does not automatically unlock/lock.” Tap it on the pillar to lock. And keep it in a wallet, not the glovebox: the manual says “do not leave a key card in the vehicle, even if you have your paired phone key with you.”
Tesla key fob not working
The fob is the one Tesla key with a battery. The manual says it “lasts for up to one year, depending on key fob version and selected vehicle settings,” that “when the battery is low, a message displays on the touchscreen,” and that the replacement is a “type CR2032” coin cell, which “can be purchased from any retailer that sells batteries.” Tesla’s shop listing notes the fob ships without one: “Batteries are not included.”
Three other fob behaviors look like faults and are not.
- It goes to sleep. “Passive locking and unlocking disables after being stationary for five minutes while within vehicle range when the vehicle is not in use.” The manual’s fix: “shake or press a button on the key fob.”
- Other electronics interfere. “Radio equipment on a similar frequency can affect the key,” so “move the key at least one foot (30 cm) away from other electronic devices (phones, laptops, etc.).”
- Some older fobs never had passive entry. “Key fobs with the Model 3 logo printed on the flat side cannot passively lock and unlock your vehicle.”
When it does work passively, the range is short by design: the car’s sensors “can recognize the presence of a key fob within a range of approximately six feet (two meters).” And pairing a fob in winter can fail for a reason the manual spells out: “Pairing a key fob that is very cold can be unsuccessful.” Warm it in a pocket first.
Why is Walk-Away Door Lock not working?
Tesla lists seven reasons. The first three: “A door or trunk is not fully closed,” “Bluetooth for the phone key is turned off,” and “a phone key or paired key fob is detected inside the vehicle.” The rest: the driver got out through a different door, “‘Exclude Home’ is active and your vehicle is parked at your Home location,” “the seat or brake system detects a person inside the vehicle,” or the car keeps detecting an authenticated key for several minutes after you leave, in which case Tesla says to “lock your vehicle manually until after your next drive.”
The second phone is the classic. Tesla’s note: “Leaving your phone in your vehicle while parked will prevent your doors from locking.” The manual is sharper about what that means: a paired phone left inside “is essentially the same as leaving your keys in your vehicle with the doors unlocked,” because the car “cannot tell whether your phone is inside or outside of the vehicle.” A partner’s paired phone in a gym bag on the back seat will do it. Tesla’s fix: “If you need to leave your phone in your vehicle and lock the doors, you will need to turn off your phone’s Bluetooth before locking the vehicle.”
How many keys can a Tesla have?
These limits are the Model 3’s; check your own car’s manual for other models. The Model 3 manual says the car “supports up to 19 keys.” The current edition adds that “four of those keys can be key fobs.” The older edition puts the live limit this way: the car “can connect to a maximum of three devices (phone keys, key fobs, or watch keys) at a time.”
Two more key types sit inside those numbers. “You can also set up an Apple Watch to be used as a key,” and “some smartphones with NFC capability can be used to lock/unlock your vehicle, just like using a key card,” by holding the phone to the driver’s door pillar.
One floor applies as well: “Model 3 requires at least one authenticated key card or key fob at all times. If only one key card remains on the key list, you cannot delete it.”
Lost your key cards? What a replacement costs
As of September 20, 2026, Tesla’s shop lists a Key Card pack at $40 that includes two key cards and a bifold wallet, in one style for the Model 3 and Model Y and another for the Model S, Model X and Cybertruck. The Model 3/Y Key Fob is $175. Check those pages for the current price before you order.
You do not need a working card to pair the new one. Tesla says that “in the event that you don’t have a working key card or key fob, you can add a new key using the Tesla app”: open the app near the car, touch Security & Drivers, then Add Key Card, and scan the new card on the console reader. Two conditions: “Only the vehicle owner can add new keys using the Tesla app,” and it “requires Tesla app version 4.29.0 or later and vehicle software version 2022.40 or later.” Afterward, the manual’s advice is to “remove your old key cards from Controls > Locks > Keys for security purposes.”
If the car is leased, the manual says to “contact your leasing company to add or remove keys.”
Which Teslas do not support a phone key?
Two groups of older cars. Tesla’s support page says: “2012-2020 Model S and 2015-2020 Model X do not support phone key.” Those cars use a fob. The replacement key card pack has its own, separate limit: it is “compatible with Model S and Model X vehicles produced in 2021+, all Model 3 and Model Y vehicles and Cybertruck.”
When no key works at all
If the phone, the card and the fob all get no response, and the car does not wake, light up or click, stop troubleshooting keys. That pattern points at the car’s low-voltage battery, the small one that runs the locks and computers, and the Tesla 12V battery guide covers the warning signs and what to do next. For the rest of living with the car, start at the Tesla owner’s guide.
Frequently asked questions
Does a Tesla phone key need internet or cell service?
No. The manual says that once authenticated, a phone “no longer requires an internet connection to be used as a phone key.” It needs Bluetooth. Unlocking from the app remotely is the part that needs a connection.
Does a Tesla key card have a battery?
Tesla’s manual does not give it one. It says the card communicates using “short range radio-frequency identification (RFID) signals,” and the only battery it tells you to replace is the key fob’s CR2032.
Where do you tap a Tesla key card?
Outside, on the driver’s side door pillar, holding it for one or two seconds. Inside, behind the cup holders on 2017 to 2023 Model 3s, or on the wireless phone charger in the current Model 3.
How long do you have to start a Tesla after using the key card?
Two minutes. After that you scan the card again on the reader inside the car.
Can you drive a Tesla away without the key?
Yes, and it is a trap. The manual warns: “Although you can drive Model 3 away from its key, you will be unable to power it back on after it powers off.”
How much is a replacement Tesla key card?
Tesla’s shop listed a pack of two cards with a wallet at $40 on September 20, 2026, and the Model 3/Y key fob at $175. Confirm the price on Tesla’s shop before ordering.
Sources (7)
- tesla.com Tesla Support: Tesla Vehicle Keys (read September 20, 2026)
- service.tesla.com Tesla Service DIY: Troubleshooting Bluetooth (Model 3)
- service.tesla.com Tesla Service DIY: Troubleshooting Bluetooth (Model Y)
- tesla.com Tesla Model 3 (2017-2023) Owner's Manual: Keys (read September 20, 2026)
- web.archive.org Tesla Model 3 Owner's Manual: Keys (Wayback capture 2025-03-23)
- shop.tesla.com Tesla Shop: Key Card (read September 20, 2026)
- shop.tesla.com Tesla Shop: Model 3/Y Key Fob (read September 20, 2026)
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