2019 Toyota Mirai Key Replacement

2019 Mirai key specs

First-generation Mirais use a four-button proximity fob with lock, unlock, trunk and panic buttons; catalogs list FCC HYQ14FBA under Toyota part 89904-62020. Touching the door handle with the fob nearby unlocks the car, and the POWER button starts the fuel-cell system whenever the fob is inside. An emergency blade slides out of the fob for the driver's door. There is no key slot or conventional ignition anywhere on the car.

What's specific to the 2019 Mirai

The 2019 Toyota Mirai is the fourth of 5 model years in the Mirai JPD10 (1st generation) (2016–2020), so it shares its key system with the rest of that run, which makes replacement parts easy to source. A 2019 Toyota Mirai is about 7 years old now. Original fob batteries are near the end of their life at this age, so weak range or a "key not detected" message is often a battery before it is a failed fob. Cars this age are often on their second owner, which is when a single remaining key and a request for a spare tend to show up.

Smart-key cars like the 2019 Mirai can be targeted with relay attacks that extend the fob's signal from inside your home, so keep fobs away from exterior walls or in a signal-blocking pouch, and have any missing fob erased from the car.

Key options for the 2019 Toyota Mirai

• Smart proximity key (push-to-start). Proximity keys bring a security trade-off worth understanding. Because the fob is always listening, thieves with relay equipment can stretch its signal from inside your house to the car in the driveway. Keeping the fob away from exterior walls, or in a signal-blocking pouch, closes that gap, and some fobs offer a sleep mode described in the owner's manual. If a smart key for your 2019 Toyota Mirai is lost or stolen, programming a replacement is the moment to delete the missing fob from the car's memory. And be wary of used fobs from online sellers: a lot of them are locked to the vehicle they came from and can't be reprogrammed to yours.

How the Toyota immobilizer works on the Mirai

Toyota phased in transponder immobilizers model by model, so two Toyotas from the same year can need very different keys. Starting with the 1998 model year, the Camry, Avalon, 4Runner, Sienna and Land Cruiser used a fixed-code Texas 4C chip, while US Corollas, the Echo and other economy models kept plain mechanical keys into the mid-2000s. Between 2003 and 2005, depending on the model, the encrypted Texas 4D-67 chip took over. Around 2010 came the 80-bit G chip, and from about 2014 the 128-bit H chip, also called 8A. Many of these later keys carry a stamped D, G or H on the blade. Smart keys spread to US Toyotas with cars like the 2004 Prius, 2005 Avalon and 2007 Camry, moved to 128-bit fobs in the 2010s, and since about 2022 Toyota has used a newer generation: Texas 8A BA-type fobs in models such as the bZ4X and Crown, and NXP Hitag AES, often called 4A, in the Corolla, Corolla Cross and 2025 Camry. Partner-built cars follow their partner's rules, so the 86 and GR86 use Subaru systems and the GR Supra uses BMW's. The letter on your blade, the FCC ID on your fob and your VIN tell us which system we are working with.

• Toyota began US retail deliveries of the Mirai in California in October 2015, as a 2016 model.
• Its HYQ14FBA fob is a four-button version with a trunk button, part 89904-62020, not the Highlander's fob with the same FCC ID.
• With a dead fob battery, the car can still be started by touching the POWER button with the fob's Toyota emblem side, per Toyota's procedure.

Programming a 2019 Mirai key

There is no on-board programming for Mirai fobs. A new fob is registered with a programmer through the OBD-II port and the smart key system, after which the emergency blade is cut to the door lock. Aftermarket tool coverage for the Mirai is thinner than for the Prius or Camry because so few were sold, so we check your VIN against our equipment before scheduling. All-keys-lost may require direct access to the smart key ECU or a visit to a Toyota fuel-cell dealer.

Adding a fob is often possible with current tools. All-keys-lost on this low-volume car may need smart key ECU access or a Toyota fuel-cell dealer.

Lost every key to your Mirai?

1. Gather your documents and the VIN. Find your registration or title and a government photo ID in the same name. Note the VIN, which is printed on the driver's side of the dashboard and usually on your insurance card. If the paperwork is locked in the car, tell us; we'll open the vehicle first and check it there.
2. Get into the vehicle without damage. If the car is locked, we open it with non-destructive tools such as an inflatable wedge and a long-reach rod, or by picking the door lock. Some vehicles need a careful approach to avoid triggering the alarm, which can interfere with programming later.
3. Originate a new key from the car. With no key to copy, the cuts come from the vehicle itself. We retrieve the key code through manufacturer channels where possible, or decode a door lock with a pick-decoder tool. Then we cut the blade on our code machine and confirm it turns the lock smoothly.
4. Program the key to the immobilizer. Next, the new key is introduced to the car's security system. Many vehicles allow this through the OBD-II port with a PIN or security procedure. Some all-keys-lost cases require reading a module on the bench, and a few platforms only allow dealer programming, which we'll tell you up front.
5. Erase missing keys and add a spare. A lost key's metal blade can still open your doors even after its chip is erased. If the keys disappeared along with something showing where you live or park, consider rekeying the car's door lock cylinders too. We'll also recommend leaving with two working keys, not one.

Why a spare key pays for itself

• A spare stored safely at home rescues you from a locked car with the fob sitting on the seat, a key dropped somewhere along a hiking trail, or a fob that stops responding on a busy morning. Keep it indoors, never in a magnetic box under the bumper.
• Two drivers sharing one key is a daily negotiation. A second key lets a partner, teenager or coworker use the vehicle without handing keys back and forth in parking lots, and it means one person losing their key ring doesn't leave the whole household stuck.
• When you sell or trade in the vehicle, buyers and dealers expect two keys. A missing key can come up during an appraisal or a private-sale negotiation, so having both on hand keeps the conversation about the car, not about what it will cost the next owner to replace one.

Dealer or mobile locksmith?

Price and parts are the other half of the comparison. Dealers typically sell factory keys only and charge their posted service rates for programming. We offer factory keys where it matters and quality aftermarket alternatives where they perform well, and the quote covers cutting, programming and the trip, with nothing tacked on at the end. Timing differs too. Dealer service departments generally keep business hours, while we take automotive calls every day from 6:30 a.m. to 11:30 p.m., which covers early commutes and late evenings. We're closed overnight, and we'll be upfront if your timing means the dealer or a next-day visit is the better plan. Neither option is wrong; the right one depends on your Mirai and your schedule.

Mirai key battery

Most fobs for a 2019 Toyota Mirai open along a small slot in the seam; a coin or a plastic pry tool works better than a screwdriver, which chews up the housing. If the fob hides a mechanical blade, slide it out first, since the case often opens from that gap. Note which side of the old cell faces up, swap in a fresh replacement, and press the halves together until they click all the way around. Handle the new battery by its edges, because skin oil on the faces can hurt contact. In most cases the fob keeps its programming through a battery change, so test lock, unlock and start, and you're done.

How the job works

1. Identify the exact key your Mirai uses. Every job starts with the VIN, the trim and a look at any key you still have. From those we confirm the keyway, the transponder or smart-key chip, the remote frequency, the FCC ID and the button layout. Two Toyota Mirai keys that look identical can carry different electronics, so this step keeps the wrong part from ever reaching the car.
2. Verify ownership before any work. Before cutting or programming, we compare your government photo ID with the vehicle registration or title and check that the VIN on the paperwork matches the VIN on the dash. If the registration is locked inside, we open the car first, confirm the documents, and only then make the key.
3. Get the key code or decode the lock. A key is cut from a code, not a guess. When the factory code can be retrieved through manufacturer channels after ownership is verified, we use it. When it can't, we decode a door lock with a pick-decoder tool that reads the wafer positions without damaging anything, then work out any missing cuts.
4. Cut the blade on-site. Our van carries a code-cutting machine that handles both traditional edge-cut blades and the laser-cut, side-milled profiles common on newer keys. The blade is cut to the code, then test-fitted in a door lock and the ignition or emergency keyhole to confirm smooth operation before any programming begins.
5. Program the chip, remote or smart key. Programming tells the car's computers that the new key belongs to the vehicle. Transponder chips are added to the immobilizer, remote buttons to the body control module, and proximity fobs to the keyless system. If a step requires dealer-only access on your Mirai, you'll have heard that before we arrived, not halfway through the job.
6. Test everything and clear out old keys. The last step is a short walkthrough. We show you how many keys the car now recognizes, point out the dead-fob start method for your vehicle, and hand you an itemized receipt. If a spare makes sense, it's simplest to add it during this same visit while the equipment is already connected.

What affects the price of a Mirai key

• The type of key. Price follows complexity. The more the key does, the more it costs to replace: brass blade, then chip, then remote buttons, then full keyless entry and push-button start. If your Mirai came with different key styles by trim, the one your car actually uses is the one that sets the quote.
• Factory or aftermarket parts. Factory keys and fobs carry the manufacturer's part number and usually the highest parts cost. Quality aftermarket keys use compatible electronics at a lower price and work well on many vehicles. We tell you which options we trust for your car, and where an aftermarket version has known range or fit issues, we steer you to OEM.
• Programming complexity and security access. Some immobilizers accept a new key with a few on-board steps. Others need a PIN code, a timed security wait, manufacturer online access, or removing a module to read its data. Every extra layer of security on the Toyota system adds equipment time and labor to the job.
• Blade style and cutting. Traditional edge-cut blades are quick to cut. High-security laser-cut blades, with a groove milled into the side, need a specialized machine and more care, and the blanks themselves cost more. If we have to decode a lock to find the cuts, that adds labor as well.

Call (951) 903-3193 with your VIN and the keys you still have, and we'll quote the job before any work starts.

Common Toyota key problems

• Many newer Toyota fobs have a battery-saving mode, switched on by holding lock and pressing unlock twice. Afterward the car ignores the fob in your pocket until a button is pressed, which owners often mistake for a dead key.
• Remote-head keys take a beating on a key ring: the plastic head cracks and the rubber button pad tears. The chip and circuit board usually survive, so a new shell and freshly cut blade often fix the problem.
• Toyota chip keys are easy to mix up. Many later keys are stamped near the head with D for the 4D-67 chip, G for the 80-bit G chip or H for the 128-bit H chip, and a key ordered by looks alone often won't program.

Tips from a mobile locksmith

• If your vehicle has a proximity key, think about where it sleeps at night. A fob hanging by the front door can sit within range of relay equipment used to open and start cars from outside. A drawer deeper inside the house, a signal-blocking pouch, or the fob's own sleep mode reduces that risk considerably.
• Make the spare before you need it. Adding a key while one still works is quicker and less expensive than starting from nothing, and it keeps the simpler programming options available. Good moments are right after buying the car, or as soon as one of your two keys goes missing.
• On any vehicle with a turn-key ignition, keep the key ring light. A heavy cluster of keys, tools and charms swings with every bump and slowly wears the ignition wafers and the key itself. When the key starts to stick or needs a wiggle to turn, deal with it early, before it stops turning entirely.

Proof of ownership

Making car keys is regulated work in California. Locksmiths are licensed and overseen by the Bureau of Security and Investigative Services under the Locksmith Act, Business and Professions Code section 6980 and following, and Julian's Locksmith holds company license LCO7891. Verification protects you more than anyone: a locksmith who will make a key for whoever asks will also make one for someone who wants your car. We record your name, the vehicle and its VIN on a work order, and we politely decline jobs where ownership can't be established. You can look up our license at search.dca.ca.gov.

Need a 2019 Toyota Mirai key?

Need a key for your 2019 Toyota Mirai? Call Julian's Locksmith at (951) 903-3193 with your VIN and tell us which keys you still have. We'll confirm what the job involves, give you a quote before any work starts, and come to you in Southern California with everything needed to cut and program the key on the spot.