Parts and service guide · Chicago Northside Toyota
Toyota Key Replacement: Fob Battery and Lost Keys
A Toyota key fob that stops working from across the parking lot usually just needs a coin cell. A fob that is lost, broken or chewed by the dog needs a replacement key cut and programmed to your car. Here is how both work.
Quick answer
To change the battery: slide the mechanical key out of the fob, open the case with a thin flat blade in the slot the key came out of, lift the coin cell out, note the type printed on it (most current Toyota smart keys use a CR2032, some older ones a CR1632) and fit the new one with the plus side up. To replace a lost or broken key: bring a photo ID, proof of ownership and your 17-digit VIN to our parts department. Toyota keys are cut to your VIN and smart keys are programmed to the car, which is why a dealer does it and why Toyota cannot locate a lost key remotely.
Signs the fob battery is low
- Shorter range: you have to be next to the car for lock, unlock or remote start to work.
- A "key battery low" message on the multi-information display at start-up.
- Keyless entry needs two or three touches of the door handle.
- The car asks you to hold the fob against the start button to start.
If the car will not start and the dash is dark, the problem is the car's 12-volt battery, not the fob.
Changing the battery step by step
- Press the release latch on the fob and slide out the mechanical key.
- Wrap a small flat screwdriver in tape, fit it into the slot the key came from and twist gently to pop the case open.
- Lift out the coin cell. Note the type printed on it before you buy a replacement; the owner's manual lists it too.
- Fit the new cell with the plus side facing the same way as the old one, snap the halves together and slide the key back in.
- Test lock, unlock and the start button. If the fob still does not work after a fresh battery, bring it in; the fob itself may need replacement.
Our parts counter stocks the coin cells and will fit one for you while you wait.
Lost or broken key: what to bring
| Key type | What we need from you | What happens |
|---|---|---|
| Mechanical key only (older Toyotas) | Photo ID, proof of ownership, VIN | Cut to the key code on file for your VIN |
| Remote-head key or separate remote | Photo ID, proof of ownership, VIN, the car | Key cut, transponder and remote programmed to the car |
| Smart key (push-button start) | Photo ID, proof of ownership, VIN, the car | Smart key registered to the car; an existing key makes this quicker |
| All keys lost | Photo ID, proof of ownership, VIN, the car | Immobilizer re-registered; allow extra time |
Toyota's guidance is the same for every dealer: the parts department verifies ownership from a valid photo ID and the VIN before ordering or cutting a key. Keep a spare: a second key makes any future replacement faster and cheaper.
If the fob dies away from home
The mechanical key inside the fob opens the driver's door. To start a push-button Toyota with a dead fob, hold the Toyota logo side of the fob against the start button while pressing the brake, then press the button. The car reads the chip in the fob even without a battery.
Frequently asked questions
What battery does a Toyota key fob take?
Most current Toyota smart keys use a CR2032 coin cell; some older smart keys use a CR1632 and some remote-head keys use a CR2016. The type is printed on the old battery and listed in your owner's manual.
How do I replace a lost Toyota key?
Bring a valid photo ID, proof of ownership and the 17-digit VIN to a Toyota dealer's parts department. The key is cut to your VIN and, for remote and smart keys, programmed to the car.
Can Toyota find my lost keys?
No. Toyota does not offer a service to remotely locate lost keys.
How do I start my Toyota if the key fob battery is dead?
Hold the fob against the start button with your foot on the brake and press the button. Use the mechanical key inside the fob to unlock the door.
Does Chicago Northside Toyota replace key fob batteries?
Yes. Our parts department stocks the coin cells and will fit one while you wait.
Need a key or a battery?
Our parts department cuts and programs Toyota keys and stocks fob batteries. Bring your ID and registration for a replacement key.
Sources
Checked against Toyota's owner support articles on October 19, 2026. Battery types vary by key style; the old battery and your owner's manual show yours.
- I need a replacement key for my vehicle. Where can I get a new key?, Toyota Motor Sales, U.S.A. support
- Smart Key support articles (dead fob battery, start button, door unlock), Toyota Motor Sales, U.S.A. support
- Toyota owner's manuals and Warranty & Maintenance Guides, Toyota Motor Sales, U.S.A.
