2004 Infiniti FX35 Key Replacement

2004 FX35 key specs

First-generation FX35s come two ways. Many use a chipped transponder key (NI04T style) with a separate keyless-entry remote, such as KBRASTU15 or CWTWB1U751. Others have Infiniti's Intelligent Key: a 2003-2004 three-button fob (FCC ID NHVWBU612) or a 2005-2008 fob (FCC ID CWTWBU619), used with a start control instead of a keyed ignition. Supplier listings show a different emergency blade (DA16, part H0564-CG005) for the 2003-2004 fob. A look at your ignition, cylinder or knob tells us which parts to bring.

What's specific to the 2004 FX35

The 2004 Infiniti FX35 is the second of 6 model years in the FX35 S50 (1st generation) (2003–2008), so it shares its key system with the rest of that run, which makes replacement parts easy to source. A 2004 Infiniti FX35 is about 22 years old. Original keys are often worn smooth, and some factory remotes for cars this age are discontinued, so we may suggest a quality aftermarket remote or a separate fob. Because older immobilizers are simpler, all-keys-lost jobs on cars this age are usually more straightforward than on late models.

Smart-key cars like the 2004 FX35 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 2004 Infiniti FX35

• Transponder (chip) key. A transponder key carries a small chip in its head, usually a glass capsule or a carbon wafer, with no battery of its own. When you turn the key in a 2004 Infiniti FX35 that uses one, an antenna ring around the ignition energizes the chip and asks for its code. If the answer matches what the immobilizer has stored, the engine is allowed to run. If it doesn't, you get the classic symptoms: the engine cranks but won't fire, or it fires and dies after a second, and the security light on the dash flashes or stays lit. That's why a perfectly cut copy without a programmed chip will open the doors but won't start the car.
• Key with separate remote fob. Separate remotes are easy to find online, which is exactly why they cause trouble. A listing can show the same shell as your Infiniti FX35 remote while hiding a different FCC ID, frequency or internal chip, and some used remotes are locked to the first vehicle they were paired with. We're glad to look at one you've already bought, and we'll tell you honestly whether it can be paired before charging you to try. If the remote side of your setup has become unreliable, it's also worth asking whether a fresh remote and a newly cut key, matched together, would cost less than chasing repairs on aging parts.
• Smart proximity key (push-to-start). A smart or proximity key lets a 2004 Infiniti FX35 open when you touch the door handle and start with a push of a button while the fob stays in your pocket or bag. Antennas in the doors and cabin send out a low-frequency wake-up signal; the fob answers on a higher radio frequency with an encrypted reply, and the car only allows a start once it confirms the fob is inside. When the fob battery is weak, that conversation fails, which is why most designs include a backup: hold the fob against the start button or set it in a designated pocket. The owner's manual shows where, and it's worth checking before you need it.

How the Infiniti immobilizer works on the FX35

Nearly every Infiniti sold in the US since 2000 has an engine immobilizer built on Nissan's NATS (Nissan Anti-Theft System). A transponder in the key or fob has to answer the car's challenge before the engine is allowed to run, and the small security light on the dash blinks while the system is armed. The chip inside changed over the years. The 1997-2001 Q45 used a fixed-code Texas 4C transponder, while the G20, I30, I35 and QX4 used the Texas Crypto 4D60. From 2003 the G35, FX and later models moved to the Philips ID46, which stayed in the Intelligent Key fobs of many models well into the 2010s. Infiniti's Intelligent Key lets the car recognize a fob in your pocket; some early cars such as the FX paired it with a turning ignition knob, and push-button start became standard on most models by about 2009. From roughly 2013 the newer fobs use different electronics, and a replacement has to match both the FCC ID and the IC number printed on the original. The QX30 is the outlier: its key system came from Mercedes-Benz.

• The S50 FX reads a Philips ID46 transponder, the same family used in the G35 of those years.
• The S51 generation was the first FX with push-button start.
• The 2005-2008 Intelligent Key fob (CWTWBU619) takes a CR2025 battery, while the 2003-2004 fob (NHVWBU612) takes a CR2032.

Programming a 2004 FX35 key

Transponder keys and Intelligent Keys are both registered to the S50's immobilizer over OBD-II using the NATS PIN, and the session rewrites the key list, so bring every key you still use. Separate remotes are programmed in their own step. All-keys-lost is handled on site: we cut a key or emergency blade by code and register new keys or fobs before we leave.

Conventional transponder-key cars are routine. Intelligent Key cars of this era can need extra steps for all-keys-lost, so we confirm key type and procedure by VIN before quoting.

Lost every key to your FX35?

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. 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. All-keys-lost programming often takes longer than adding a key, because the car has no trusted key to authorize the change. We follow the procedure your Infiniti FX35 requires, then confirm the engine starts and keeps running and the remote or keyless functions respond.
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

• Electronics fail without warning. A fob dropped on concrete, run through the washing machine or soaked at the pool can quit for good. With a second programmed key, that's an annoyance you fix on your own schedule, not a stranded car that needs attention today.
• 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.
• 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?

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 Infiniti FX35, ask us directly and you'll get a plain answer.

FX35 key battery

A fob battery rarely dies all at once. The warning signs build: you have to get closer to the car before the doors respond, the dash shows a key battery or key-not-detected message, or the push-button start only works with the fob held near the button. Inland heat speeds that decline, especially for fobs left in a hot cabin or on the dashboard. Keep a spare replacement at home in a cool drawer, sealed in its original package, and buy from a busy store where stock turns over quickly. A cell that sat on a shelf for years may arrive already partly spent.

How the job works

1. Identify the exact key your FX35 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 Infiniti FX35 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. California holds licensed locksmiths responsible for knowing whose car they're making keys for. We record your name, the VIN and the plate on a work order. If you aren't the registered owner, you'll need the owner's written authorization along with your own photo ID before we begin.
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. With the blade done, we connect to the OBD-II port and register the new key with the immobilizer. Depending on the Infiniti system, this may involve a security PIN, a timed waiting period, or on-board button sequences for the remote. On some vehicles we clone a working key's chip instead, when that's the more reliable path.
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 an FX35 key

• The type of key. The biggest factor is technology. A plain mechanical key is a cutting job only. A transponder key adds a chip and programming. Remote-head and flip keys add a circuit board, and a proximity fob for a push-button Infiniti FX35 is the most involved of all, both in the part itself and in the programming.
• All keys lost or adding a key. Adding a key while a working one is in hand is the simpler job. With every key gone, we may have to open the car, decode a lock to originate the cuts, and run a longer programming routine, so all-keys-lost work takes more time and costs more.
• 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 Infiniti 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 Infiniti key problems

• Some late-2000s push-button Infinitis can show a steering-lock fault that looks like a key problem: the car refuses to start and the dash flags the steering lock. That points to a column-module repair, not a new fob.
• On older turn-key models like the I35, G35 and QX4, worn keys and ignition wafers cause sticking or no-turn ignitions. Cutting a fresh key by code, rather than copying a worn one, often solves it.
• A dead 12-volt battery can leave you outside a push-button Infiniti even with a good fob. The mechanical key hidden inside the fob opens the driver's door so you can reach the hood release.

Tips from a mobile locksmith

• 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.
• Southern California heat is hard on keys. Fob batteries drain faster, plastic housings turn brittle, and rubber button pads crack when a key spends summer afternoons on a dashboard or in a sunny cup holder. Carry the fob with you or keep it shaded, and replace batteries before summer rather than after they fail.
• 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.

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 2004 Infiniti FX35 key?

Locked out, keyless, or just tired of a fob that only works half the time? Julian's Locksmith can help with your FX35 in Southern California. Have your registration and photo ID ready, call (951) 903-3193, and we'll give you an honest answer about what we can do on-site and what it will cost before we head your way.