2021 Toyota Sienna Key Replacement

The 2021–2026 Sienna uses the same key setup, so everything on this page applies to those years too. The full picture is on the Toyota Sienna key guide.

2021 Toyota Sienna: key facts

Key type: Smart / proximity key
Push-to-start: Yes
Transponder chip: 8A-BA (128-bit DST-AES smart)
Programming: OBD
All keys lost: We can originate new keys on site

Hybrid-only XL40 with push-button start standard; 8A-BA smart system. For all-keys-lost on 2020+ smart-key cars, US jobs generally require Toyota server codes with locksmith-credentialed (LSID/NASTF VSP) TIS access; add-a-key with a working fob is less restricted.

What kind of key does the 2021 Sienna use?

Every 2021 Sienna is a hybrid with push-button start as standard, so there is no ignition keyway to turn. The car uses a smart proximity key. It talks to the vehicle through an 8A-BA chip, a 128-bit DST-AES smart system, and the car authenticates the fob before it lets the system start. That is why a plain hardware-store copy will not do anything here.

For you as the owner, this means two things. First, a replacement fob has to be programmed to the van, not just made. Second, the programming is done through the OBD port under the dash with proper diagnostic equipment. Our data on this chip family is verified.

Your fob also holds a mechanical backup key. It is meant for getting into the van if the fob battery dies. It does not start the vehicle by itself. If you still have it, keep it somewhere safe, not in the van.

Spare fob or all keys lost: what's different?

Making a copy of a smart key needs an original working key. If you still have one fob, adding another is the less restricted job. If you have none, it is an all-keys-lost job. That is possible on this Sienna, but it is more involved.

On 2020 and newer smart-key Toyotas, an all-keys-lost job generally needs Toyota server codes, and that access is tied to locksmith credentials through NASTF. This is a real restriction, not a way to pad the job. We will tell you plainly when you call whether we can finish it where the van is parked or whether the dealer is the realistic route.

Tell us the situation: how many working fobs you have, if any, and whether the van will unlock with the mechanical key.
Give us the VIN so we can confirm the exact system rather than guess from the model year.
We confirm you are the owner and check the van's ID and registration.
For a spare, we program a new fob from a working one through the OBD port. For all keys lost, we get the required security data first, then program.
We test every fob: unlock, lock, push-button start, and the mechanical backup key.

What affects the cost of a 2021 Sienna key?

Smart fobs for this van cost more than the bladed keys on older vehicles. That is simply the hardware and the programming involved. We do not quote numbers on a web page because the real answer depends on your situation. These are the factors:

Whether you have a working fob. A spare is usually the more economical route compared with all keys lost.
Whether security data from Toyota is required, which it generally is when every key is gone.
How many fobs you want programmed in one visit.
Where the van is. Mobile service to your location differs from you coming to our Westwood storefront.
The condition of an existing fob. A fob with a dead battery may only need a battery, not a replacement.

Locked out or need a locksmith now?

We answer around the clock, every day of the year.

Call (213) 577-1366

A common problem: 'key not detected'

Before you replace a fob, try a fresh battery. A 'key not detected' message is a common complaint on this van, and a weak battery is a frequent cause. Water-damaged fobs are another known issue. If a fob has been through a wash or a spilled drink, the electronics may be the problem, and a new battery will not fix it.

If the fob still starts the van when held to the start button but fails otherwise, tell us. That points toward a battery or a failing fob rather than a lost key.

What we confirm by VIN

The chip family and programming method above are verified for the 2021 Sienna. What we do not claim from a web page is the exact fob button layout on your specific trim, or whether your particular van has any mid-year differences. We confirm that by VIN or in person before we order or cut anything.

California requires locksmith companies to hold a BSIS LCO license, and you should ask any locksmith for it before they work on your vehicle.

Wilshire Lock & Key has been in business since 1987, with a storefront at 10740 Wilshire Blvd in Los Angeles and mobile service vans. One company handles your call, with no dispatch middlemen, and David oversees the work. For more on this model, see the Toyota Sienna key page, the broader Toyota key guide, or contact us directly.

Frequently asked questions

Can you make a 2021 Sienna key if I lost every fob?

It is possible, but it is an all-keys-lost job. On 2020 and newer smart-key Toyotas, it generally requires Toyota security data tied to locksmith credentials. Call (213) 577-1366 with your VIN and we will tell you honestly whether we can do it on site or whether the dealer is the better path.

Is it easier if I still have one working fob?

Yes. Adding a fob when you have a working one is less restricted than all keys lost, and it is usually the more economical route. Do it before the last fob is gone.

Does the 2021 Sienna have push-button start?

Yes. It is a hybrid-only model with push-button start as standard, using a smart proximity key and an 8A-BA chip system.

What is the metal key inside the fob for?

It is a mechanical backup key for opening the door if the fob battery is dead. It does not start the van.

My Sienna says 'key not detected'. Do I need a new fob?

Not always. Try a fresh battery first, since that is a common cause. If the fob got wet or the message continues, the fob itself may be failing and we can test it.

How is a replacement fob programmed?

Through the OBD port under the dash, using diagnostic equipment. The fob has to be programmed to the van, because it will not work just from being cut or assembled.

Can you come to me?

Yes. We run mobile vans across Los Angeles and Ventura counties, and you can also come to our Westwood storefront. See our car key services or call us any hour.

We cover all these cities

Reviewed by David, Owner & Lead Technician, Wilshire Lock & Key — in the locksmith trade since 1987.

Last updated 2026-10-11.