2021 Ford Mustang Key Replacement

The 2021–2023 Mustang uses the same key setup, so everything on this page applies to those years too. The full picture is on the Ford Mustang key guide.

2021 Ford Mustang: key facts

Key type: Smart / proximity key
Push-to-start: Yes
Transponder chip: Varies by trim — we confirm by VIN
Programming: Confirmed per vehicle — call us
All keys lost: Depends on trim — call to confirm

Final S550 years; push-button start standard. Chip family is our era knowledge, not verified this session. NASTF's own service guidance confirms PATS functions through Ford FDRS/FJDS with a non-dealer login require NASTF VSP credentials or an OEM-assisted immobilizer request; aftermarket tool coverage for these years varies — we confirm current coverage before quoting, and say plainly if a job is dealer-or-VSP-only.

What kind of key does a 2021 Mustang use?

The 2021 model year is one of the last for the S550 generation of the Mustang, and it comes with push-button start as standard. That means the key is a smart-proximity fob: the car senses the fob nearby, so you do not insert anything to start the engine. It is not a plain bladed key with a chip in the head, like the older Mustangs many people still picture.

Inside the fob is a mechanical backup blade. If the fob battery dies, that blade still opens the driver's door, which matters because a dead fob is the most common complaint we hear on this setup. The car shows 'No key detected' even though you are holding the fob. The door still opens with the blade, but the car will not treat the fob as present until the problem is sorted out.

The three problems that come up most on these fobs are dead batteries, the higher cost of replacing a lost fob compared with older bladed keys, and fobs that have been water-damaged or crushed. If you want the wider picture for the model, our Ford Mustang key page covers the other years.

Duplicate key or all keys lost: what changes?

For this setup, making a copy needs an original key. If you have one working fob, adding a spare is the more economical route, because we are cloning or adding to a car that already recognizes a key you hold.

If every fob is gone, the job is different and we will not pretend otherwise. Whether an all-keys-lost job can be done on the road for this exact car is not something we have confirmed in our data, so we check it by VIN before we promise anything. Some of these jobs can be done by a locksmith with the right tool coverage. Others end up needing the dealer or an OEM-assisted request.

One working fob: usually the simpler job, and often the lighter-cost one.
No working fob: we confirm by VIN first, and we tell you plainly if it is dealer-or-VSP-only.
Fob works but the battery is weak: sometimes you do not need a new key at all.

What affects the price of a 2021 Mustang key?

We do not quote numbers on a web page, because the real figure depends on the situation in front of us. These are the factors that move it:

Whether you have a working original fob or none at all.
How many fobs you want made, since a spare made alongside a replacement is often more efficient than a separate trip later.
Whether the job can be done by us with available tool coverage, or has to go through the dealer or an OEM-assisted immobilizer request.
The condition of the old fob: a battery swap is a very different job from replacing a water-damaged or crushed one.
Where the car is and what time you call. We run a Westwood storefront and mobile vans, and after-hours calls can affect the total.
Smart fobs for this car cost more than older bladed keys, which is simply the hardware.

Locked out or need a locksmith now?

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

Call (213) 577-1366

What we have not verified, and how we handle it

Our records list this year's transponder as a 128-bit chip in the Hitag Pro family, but that is based on what we know of the era, not on a source we verified for this page. The programming method for the 2021 Mustang is also not confirmed in our data, and neither is whether the job requires NASTF VSP credentials.

What we do know is that Ford's immobilizer (PATS) functions through the Ford factory tools with a non-dealer login need NASTF VSP credentials or an OEM-assisted request, and that aftermarket tool coverage for these years varies. So before we quote, we check your VIN against our current coverage. If your car turns out to be dealer-only, we say so rather than have you pay for a visit that cannot finish the job.

Call (213) 577-1366 and give us the VIN, usually visible on the dash at the base of the windshield or on the driver's door jamb.
Tell us how many working fobs you have, including any with a weak battery.
We confirm what can be done and what the job involves before anyone drives out.
If it is within our coverage, we do the work. If not, we tell you the right next step.

Why call Wilshire Lock & Key

We have been in business since 1987, with a storefront at 10740 Wilshire Blvd in Westwood and mobile vans serving 140 cities across Los Angeles and Ventura counties. You reach one company, not a dispatch middleman, and David oversees the work. The phone is answered 24 hours a day, every day of the year.

California requires locksmith companies to hold a BSIS LCO license, and you should ask any locksmith for that number, including us. For other makes, start at our Ford key hub or the full car keys section. To reach us without calling, use the contact page.

Frequently asked questions

My 2021 Mustang says 'No key detected'. Is the fob broken?

Often it is just a dead fob battery. The hidden emergency blade in the fob will still open the door. If a fresh battery does not fix it, the fob may be damaged, and we can look at it.

Can you make a spare if I only have one fob?

Yes, in most cases. Duplication on this setup needs an original key, and having one working fob is the easiest starting point. We confirm coverage by VIN first.

What if I have lost every key to my 2021 Mustang?

We cannot say it is always possible on the road. We check your VIN against our current tool coverage, and if the job is dealer-or-VSP-only, we tell you that plainly.

Does the 2021 Mustang use a transponder chip?

Our records show a 128-bit chip in the Hitag Pro family, but we have not verified that for this year. We confirm by VIN and in person before relying on it.

Why does a smart fob cost more than an older Mustang key?

It contains a proximity transmitter, the chip, and a backup blade, and it must be matched to the car's immobilizer. An older bladed key is simpler hardware.

Can a damaged or water-soaked fob be saved?

Sometimes. A weak battery is easy to fix, but a water-damaged or crushed fob often needs replacing. Bring it in or describe the damage when you call.

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

Last updated 2026-10-11.