2018 Subaru WRX STI Key Replacement

2018 WRX STI key specs

From 2015 the STI shares the WRX's keys. Most cars carry a four-button remote-head key with a side-cut blade, and upper trims add Keyless Access with push-button start and a fob that hides an emergency blade. Subaru's bulletin shows the 2015 smart key using a different emergency blade from 2016 and later cars. The 2020 WRX remote-head key has a new part number, so match your old key before you order anything online.

What's specific to the 2018 WRX STI

The 2018 Subaru WRX STI is the fourth of 7 model years in the WRX STI VA (2015–2021), so it shares its key system with the rest of that run, which makes replacement parts easy to source.

At roughly 8 years old, a 2018 Subaru WRX STI has usually seen real wear. Ignition and door cylinders on high-mileage cars wear along with the key, so we cut new keys to factory code rather than copying a worn key. Fob cases crack, buttons wear through and solder joints loosen at this age, so a new shell or a replacement remote often beats repairing the old one. Many have changed hands more than once, so erasing keys you can't account for is worth doing during the visit.

Key options for the 2018 Subaru WRX STI

• Remote head key. Remote-head keys look similar across many vehicles, but the electronics inside are not interchangeable. Getting the right one for a Subaru WRX STI means matching the FCC ID and part number printed on the back or inside the case, the operating frequency, which is commonly 315 MHz on US-market cars, the transponder type, and the button layout. A trim with remote start or a power liftgate may use a four- or five-button version where a base trim uses three. We check those details against your VIN and your existing key, if you have one, before cutting the blade. A wrong match can look perfect and still refuse to program.
• Smart proximity key (push-to-start). Making a new smart key is mostly a programming job. The fob has to match the vehicle's FCC ID, frequency and chip, and then the keyless system must be told to accept it, normally through the OBD-II port. Depending on the platform, that can mean entering a PIN, waiting through a timed security procedure, or on some newer vehicles, using manufacturer online access. When every key is lost, certain models need a module removed and read on the bench. For your Subaru WRX STI VA, we'll tell you which of those applies, and if a step is dealer-only, you'll hear it before we drive out. The emergency blade hidden inside the fob is cut by code during the same visit.

How the Subaru immobilizer works on the WRX STI

• Subaru's bulletin groups the WRX and STI together for every key listing from 2008 through 2020.
• Published specifications for the ADS2255 add-a-key software list 2015-2020 STI models for Keyless Access keys when a working key is present.
• Subaru ended US STI sales after the 2021 model year.

Programming a 2018 WRX STI key

Remote-head keys and smart fobs both go in through the OBD-II port when a working key is present, and the remote is registered in the same pass. A smart fob must be new or reset to blank. With every key lost, remote-head cars follow Subaru's immobilizer procedure and are usually fine, while Keyless Access cars may need special tools. We check the chip on 2020-2021 cars before ordering a replacement.

Spare keys are routine. All-keys-lost on remote-head cars is usually fine, but Keyless Access cars can need special tools or the dealer.

Lost every key to your WRX STI?

With every key gone, the model year decides the job. A 2000-2004 Subaru, a Baja, or a base model built before its line got an immobilizer just needs a key cut by code or by decoding the door lock. On 4D62 cars from 2005 through 2011 and on remote-head cars of the G-chip years, we cut the blade, erase the missing keys and program new ones in one visit. Keyless Access cars of the G-chip years and every H-chip car are harder: some tools need a working key, so we use dedicated Subaru software or an emulator, and a few cars have to go to the dealer. Brand-new platforms, including the 2026 Outback and Subaru's electric models, are usually dealer jobs for now. We tell you plainly which route your car needs and check ID and proof of ownership before any work.

1. Gather your documents and the VIN. Call with the year, make, model and VIN if you can read it through the windshield, plus where the car is parked. Those details let us confirm whether your Subaru WRX STI can be done on-site and bring the right key, so the first trip is the only trip.
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. Originating a key means building it without a sample. The door lock usually reveals most of the cuts; any it doesn't are worked out by test-cutting and trying the ignition or a second lock. The finished blade should feel like a factory key, not a forced fit.
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. Once the car starts, we remove the lost keys from memory wherever the system allows, so they can't start the engine if someone finds them. Making a second key during the same visit costs much less than a repeat all-keys-lost call down the road.

Why a spare key pays for itself

• Some vehicles make it hard to add a key once you're down to one. Certain immobilizer systems let an owner program an extra key on-board only when two working keys are present, so a second key preserves the easy options for later and avoids a full reset.
• 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.
• 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.

Dealer or mobile locksmith?

Dealers have one clear advantage: direct access to the manufacturer's own systems. Some newer vehicles tie key programming to online authorization that only a dealer can use, and certain all-keys-lost situations on specific platforms still require it. A good locksmith knows where those lines are. Where we can do the job, we use professional programming equipment that talks to the same immobilizer and keyless systems through the OBD-II port, and in many cases the result is identical: a properly registered key that starts the car. Where we can't, we can often still help by opening the vehicle, cutting a mechanical blade from code, or helping you gather what the dealer will ask for so that visit goes smoothly. For your Subaru WRX STI, ask us directly and you'll get a plain answer.

WRX STI key battery

Battery details for the 2018 WRX STI: CR1620 (remote-head key); CR2032 (smart fob). Swap cells one at a time and match each one exactly; if a key still fails with a fresh battery, the board, buttons or programming may be the problem, which we can test on site.

How the job works

1. Identify the exact key your WRX STI 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 Subaru WRX STI 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. Cutting happens right beside your car. For a smart key, that means the emergency blade hidden inside the fob; for a transponder or remote-head key, it's the main blade you'll use every day. We deburr the cuts and check the fit in each lock so nothing binds or sticks later on.
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 WRX STI, you'll have heard that before we arrived, not halfway through the job.
6. Test everything and clear out old keys. Before we leave, every function gets checked: doors, trunk or liftgate, panic button, remote range, engine start, and the emergency blade in the driver's door. If keys are missing, we delete them from the car's memory where the system allows, so a lost key can no longer start the engine.

What affects the price of a WRX STI 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 WRX STI came with different key styles by trim, the one your car actually uses is the one that sets the quote.
• Factory or aftermarket parts. Some owners want an exact factory match; others just want a dependable key that starts the car. Both are reasonable choices. The part you pick changes the quote, so we lay out the options side by side, with the trade-offs in fit, button feel and long-term durability, before you decide.
• Programming complexity and security access. Two cars with similar-looking keys can program very differently. Newer platforms often guard key programming behind encrypted access or paid credentials, while older systems allow straightforward OBD-II pairing. We check the exact procedure for your VIN before quoting, so the number reflects the real work involved.
• Travel, timing and extra repairs. Sometimes a key problem is really a lock problem: an ignition that won't turn even with the right key, or a door cylinder that has been jammed for years. Fixing those is separate work. We point them out, explain the options, and quote the whole job up front so the bill holds no surprises.

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

Common Subaru key problems

• If a Keyless Access fob battery dies, the car can usually still be started with the backup method in the owner's manual, which uses the fob and the start button. The emergency blade hidden in the fob opens the driver's door.
• Remote-head key shells tend to crack at the blade root after years on a heavy keyring. The remote board and transponder can usually be moved into a new shell with a freshly cut blade, which often costs less than a complete new key.
• Subaru smart keys use different emergency blades. Subaru's bulletin lists a 5+4 laser-cut emergency key for the 2014-2015 Forester, the 2014 Crosstrek Hybrid and the 2015 WRX, and a thinner 4+4 key on later cars. Cut the blade to match your fob, not just the model name.
• Between 2005 and 2008 Subaru fitted immobilizers by trim, so a base Forester or Impreza of those years may have no chip while the turbocharged version does. Check before buying blanks, because a chipless copy won't start an XT, WRX or STi.

Tips from a mobile locksmith

• Photograph the back of your fob and any key tag that came with the car. The FCC ID, part number and key code printed there make ordering a replacement faster and more accurate. Store the photos somewhere you can reach from any device, not only on the phone that might go missing along with the keys.
• When a key's head cracks or its blade bends, replace it before it fails. A transponder chip can slip out of a split head, and a bent blade can break off inside the ignition or door lock, turning a simple key replacement into an extraction and repair job. Small symptoms are the inexpensive time to act.
• Never hide a spare key or fob on the outside of the car. Magnetic boxes in wheel wells and under bumpers are the first places a thief checks, and with a proximity fob, a hidden key can let anyone open the doors and drive away. Keep the spare at home or with someone you trust.

Proof of ownership

Not every situation fits the simple case, so here's how we handle the common exceptions. For a leased or financed vehicle, a registration that lists you as the registered owner or lessee works with your ID. If you just bought the car, bring the signed title or bill of sale along with your ID. For a company or fleet vehicle, we need written authorization from the business plus the driver's ID. If the car belongs to a family member, the registered owner should be present or provide signed permission and a copy of their ID. Rental vehicles go through the rental company.

Need a 2018 Subaru WRX STI key?

Don't wait until the last key disappears. If your Subaru WRX STI is down to one key, or the one you have is falling apart, call (951) 903-3193. We're a licensed California locksmith, license LCO7891, serving Southern California and the rest of the Inland Empire with mobile car key service every day from 6:30 a.m. to 11:30 p.m.